Act 3 ending

I'm just getting into this game and painfully managed to finish act 3. I tried literally like a dozen times to fight the boss battle with the nether brain and save Gale, but I literally could not do it without those stupid mind flayers knocking the damn emperor on his ass every 10 seconds. I called in every reinforcement and everything sigh sorry Gale 😅

Anyways, I got to the very end and I had Karlach and Astarion in my party. I romanced Astarion and of course was devastated to see him smoking and run off (no ascension) but the worst part was Karlach?? Seemed like my literal only options were for her to die a miserable death or go with her to avernus, leaving behind Astarion. So, I went with her. At the end celebration Astarion was a bit cold and was basically like okay go have fun in avernus then. Kind of sucks because I spent the whole game romancing him and I really enjoyed his character arc. I googled it after and found minor workarounds like turning Karlach into the mindflayer or having Wyll go with her to Avernus instead but like this ending just sucked so much?? I lost my relationship with Astarion and now I get to spend the rest of my life in literal hell just hoping we find a solution? Such a sad and depressing ending. I really wish Larian would have given both of these characters a happier ending. I also felt like most of the characters I spoke to at the party had pretty boring lives now. Halsin just went back to being a bear and Shadowheart is wandering around and sleeping outside?? Like okayyyyy? 😂

Also, hated act 3. So much noise and so much chaos and I completed 0 side quests here because I was thissss close to just giving up and starting a new campaign. I stuck it out just to finish it and I'm almost disappointed that I did. I feel like the better ending would've been to have Karlach turn and maybe I would've been able to beat the last battle somehow. And I'm on the easiest mode too! Crazy honestly

Rant over. Loved every bit of the first two acts and will be playing hundreds of hours on it. Hopefully I can figure out a less depressing ending! What are y'all's suggestions for end battle characters?