am I in the wrong ?

[PART 1] I 16 female used to be friends with "J" (16M). We were in the same school and Co-curriculum activity(CCA) for 4 years but only started talking to each other at the end of year 3 due to CCA commitments. I already had some close friends in the CCA so i decided to form a group chat with those friends and invited him to our friend group. Things were fine during the holidays as we all started to warm up to him and vice versa and actually enjoyed talking to one another. He started telling us about his ex-crush and would constantly rant in the grp chat about how she ghosted him and till now still have not replied to his messages. I have seen his messages to her before and found them quite personal but im in no place to judge as i never knew the closeness of their friendship. He would also constantly complain about his mum's bad treatment of him , his sister and his dad but whenever we give him advice he tells us thats just how she is. After 4 months of his constant rants , some of my friends in the chat started to feel uneasy and a little annoyed. Don't get me wrong I feel horrible that he has to endure his mum's horrible treatment of the family (e.g. locking them out of the house when she's mad , scolding them for showering without asking her whether she wants to shower first etc) and also having a friend ghost u out of the blue and watching the friendship end like that , nobody should ever go through that. However , we were annoyed at the fact that he would always barge into our conversations with these repetitive stories and put all the attention on him. As 16 year old teens , some of us would obviously be telling friends about our crushes etc etc but whenever myself or another one of my friend are talking about our crush and being delulu , he would barge into the convo and be like "yall are so lucky u r still friends with ur crush....mine ghosted me..." and we would always have to comfort him. Comforting him wasnt the problem , the problem was the one time we didnt comfort him because we all coincidentally had our own things to attend to (i promise it wasnt on purpose it was just bad timing coincidence) , he complained to a good friend of mine (whom i introduced him (J) to 2 months ago so that we could game together) and said that we were ignoring him and ostracizing him because we are all in the same class and dont want to hangout with him anymore. Obviously my friend told me about it because he (the friend) didnt really believe J's story and me and said friend has been friends since primary school. I got a little annoyed and set some things straight with J and he apologized and said he understood. A little while later , he finally got a new crush and started cursing abt his 1st crush , saying that she replaced him with another guy in her new class (we change classes in year 3) and how she was a bad friend yada yada yada. We all pitied him because the friend J said he got replaced with was quite infamous in the school (an F-boy some may say) but none of us really said anything and told him to forget about her since he already has another crush. The new crush is a girl in the class next door who also used to be in the same lower sec class as him. However after about 1 or 2 months of texting she suddenly blocked him without any reasoning and he was damm sad and we all pitied him again but prelims were already coming so nobody really paid much attention. After that life went on as normal for abit but he started to like subtly headpat me and try to take the same mrt with me after-school even tho I walk to the mrt with my friends but me and J gets off at the same station and goes to the same interchange just that we end up leaving on different direction trains (we lice on different ends of the mrt line) and i felt abit uncomfortable and did tell him to stop bcz idl people headpatting me unless they are in my inner circle and he definitely was not and I told him multiple times but he always apologize and do the same thing still which was very annoying to me. Around prelims season , I started becoming closer to this other friendgrp bcz we play the same mobile game and so I invited J and another friend of mine into the grpchat (I had permission from the original grp members themselves). I became very close to this one particular guy who is classmates with J , let's call him R. He's a very loud , doesn't think bfr he speaks kinda guy but he's very nice and funny to be around and I found his presence quite fun to hang around with. I tried including R and J whenever i wld see either one of them alone but J somehow always rejected the invite and chose to leave alone so i ended up becoming much closer to R bcz we vibed better and I felt more comfortable around him bcz he immediately understood my boundaries and kept to them which was something J had never done the past year. During Os period , things escalated when J started subtly targeting R by trying to talk R down on everything R says and just always trying to start arguments with R and making me have to choose whether i wanted to side with J or R , both of them knowing damm well I despise people making me choose between 2 friends bcz I rly don't see the point especially when it was J who didn't want to get along despite the multiple invites. It got to a point where during Os i told J we should stop being friends bcz I cldnt focus on my final exam preparations anymore bcz of this whole mess and siding people which was taking a toll on my already crushed mental health from the exam stress. J initially apologized and agreed and i told him my boundaries again for the 4th time. However after 2 days , he started acting like nothing had happened and that we were still the best of friends (we never were) and continued speaking for me on groupchats without myself knowing and bringing up my personal stuff that I said in the cca group chat bcz i trusted the people there but not the other group chat wirh the newfound batch of friends which I found extremely intrusive and J knew i didn't like this but he still did it. I decided if he didn't want to listen then i had no choice but to ignore him and ghost him which is a very asshole move I do not recommend unless necessary. After Os , the new friend grp (call it grp B for contexts sake) always hung out like once or twice a week. Our 1st hangout tgt was going to that good friend of mine i mentioned at the start of this whole rant who was coincidentally part of grp B. Apparently J told that friend (let's call him Z) that he wanted to go solely to try and make amends with me but I wasn't aware and he never tried to talk and he was still making jabs at R which irked me so much thruout the day so I didn't talk to him unless really necessary which was like 3 lines maximum that day and he left early during dinner so i didn't have to take the same mrt as him LOL. The next day , we went for AFA but J told the group last minute the day before that he couldn't make it (in reality he could make it but he didn't want to be ostracized by us in grp B who were all going bcz he felt left out when we went to friend Z's house which didn't make sense bcz even I myself tried to include him in the activities like Mario kart and just dance without speaking to him directly and R was trying so hard to include him in games) so everyone in grp B were kinda pissed at him for the last min but we found another person to take J's ticket so alls good.