Oh dang I never thought I'd open up TH forums to see this. Hi! Yes! I grew up with the older bionicle stuff-somewhat, they had stopped making them waaaaaay before I got into them as a kid but I got interested through the lego books + borrowing the comics from the library! Bionicle was the absolute best thing ever as a young kid, I still think I have a box of the comics and other books under my bed, and I'm sure I've still got the movies upstairs somewhere fjfkfj I watched all the movies so much that they were burnt into my brain, I should rewatch them and see if I really remember as much as I think I do. I can still vividly rememeber plot elements, not sure how accurate they are.
I don't really use reddit much/idk how accurate this is but I did see this masterpost once, on the subject of the lore! I ... also remember how convoluted the lore was, and I got so invested in it as a kid though KDHDKS if you asked me about the lore as a kid I'm sure I would've given you a whole essay on the subject
I won't be able to accurately discuss lore and characters and stuff nowadays since I don't remember a lot, and I never actually got invested with the fandom (wasnt allowed on many sites as a kid, thank god), so I'm not sure what the atmosphere/jokes are like there. But I can definitely chat about my personal nostalgia about it!
Mask of Light was hands-down my favorite though. I remember I really really liked the villains, the designs of the rahkshi were my absolute FAVORITES and I loved all their powers and stuff, and I really liked the main villain at the end too. On the subject of villains though, I really liked Sidorak and Roodaka a lot in the Web of Shadows movie, they were really entertaining if I remember right. That movie kinda scared me as a kid because I was terrified of spiders, but I did like it a lot nonetheless. I think I was mostly interested in the villains in general, not really the heroes, on second thought tbh. They were a lot more interesting to me.