I felt so related to this post, same thing has been happening for me since I while ago. My watch list keeps growing and I just don't watch anything, I get distracted with something else.
But I don't think it means you stopped liking anime, I believe that it's simply a matter of attention. If it doesn't really get your attention, it doesn't matter if it's anime or not, you will simply not watch it (or end watching it). Sometimes we get driven by other type of stories and that's fine, we have our time when we watch a certain type of entertainment and then another.
Replying to your question about which one to watch (or keep watching) from your list, it depends on the type of stories you're getting more interested right now in general. If you're looking for a strong and complex story, definitely go for Attack on Titan. But of you're looking for a light and fun plot, then Spy x Family
Yes, there are definitely a lot of things that go into making a decision to watch a series. And mostly it depends mostly on my mood. Sometimes I want to watch something cheerful, sometimes some drama, sometimes action or else something romantic.
I panicked while making this post because I didn't know that my list was so long, but that doesn't mean that I will stop watching anime or that I stopped liking it. Maybe I'll take some time and rest from this genre until I feel like going back to my favorite stories.
Thanks for stopping by and commenting, I really appreciate it! 🧡