This took a few tries, so here is everything I found.
I got Cowboys & Aliens, but technically that doesn't work for the xkcd rules because that movie came out the month before my 18th birthday. Very close though. And I guess it's kind of a case of so bad it's good, for most people, but for me, it's the James Bond / Indiana Jones crossover I always wanted and it's probably the closest thing I'll ever get.
I enjoyed Aladdin (2019), Don't Look Up, and Don't Worry Darling but I wouldn't say they are among my favorite films. They only meet the requirement for reviewer score though. And I think audience score is where it's at for this challenge. Suicide Squad works for this version of the challenge, but not for xkcd on audience score. Anyone can like a film that did poorly with critics.
This is probably going to end poorly for me, but for the rules as written xkcd challenge, I got Pixels. It's an Adam Sandler movie, and I know some people don't like those. I'm not crazy about Adam Sandler films, but this one was about video games and I really enjoyed it. I think Sandler did it justice. His experience with video games seemed to be primarily from arcades, but I think that is a valid perspective.
I watched it with my roommate during college. I guess some people hate it because they feel the original vision wasn't done justice for the short film it was based on. I might have seen some of that original short film, I can't rule that out for certain. But based on the version I found on youtube while writing this I clearly hadn't. The controversy didn't detract from my enjoyment of Pixels.