So many questions so much unanswered

I recently finished the show and I can’t quite figure it out. I feel stupid having to post, but did he do it?

I feel like it was implied , but there was never like a solid idea of it. I know there was CCTV footage but they didn’t elaborate to the audience what exactly was seen.

I don’t know if I was holding out for a plot twist or what .

Also, I feel like there’s so much more to the story with Jade. Her characters appearance was very riveting, there was no explanation as to why she didn’t want to go home , and why she felt like Katie’s parents didn’t like her.

There was no explanation as to why Adam wasn’t on the best terms with his father.

There was no explanation to why Tommy, who had been friends with Jamie didn’t doubt he did it, but seemed very aloof and eager to step away

Also, I didn’t quite understand the manipulation aspect about the pickle sandwich I read on a Netflix sub that he lied about not liking pickles, but I never seen him eat the pickles so I don’t get it