Friendship trouble

I'm not super sure if this fits in this forum since most of it seems to be romantic relationship focused, but I thought it may be helpful to get other people's input on my situation.

I have a best friend that I've known since high school. At this point I would have met him about 10 years ago. We've been friends since we met as we have a lot of similar interests in music, movies, cartoons, video games, that sort of thing. We haven't always been in contact all the time since a lot happened in our individual lives since graduating high school (normal) but we've always at least been able to text each other on the odd occasion and meet up to do something. We would sometimes play video games with each other whenever we would get the chance, even if neither of us has super great machines and we were sometimes limited to mobile games. We saw each other a lot more during the pandemic since we lived relatively close to each other, but after restrictions were lessened I ended up having to move away for work and we haven't been able to see each other as much. We've still been in contact a lot even if we were just talking about nonsense, but lately I haven't heard back from him. I would try to text him occasionally but I haven't gotten a response from him for months. I've tried calling him but it would always go straight to voicemail, which he wouldn't respond to. My mind has gone to a few different places on what is going on, but the most distressing is that he simply doesn't like me anymore and has completely cut me off. If I think about that logically I don't think it makes much sense, but a lot of the time I can't help but feel that way. I keep thinking that maybe I took too long to return texts or I just wasn't very engaging when we were talking with each other and that eventually he just got sick of me. That's an absurd thought and doesn't fit him at all, but it doesn't really change how I feel. I've always had kinda low self esteem and have been worried that people are at best just putting up with me.

I may be overthinking this but I really don't know how to respond to this situation. Continuous texting seems like it's at best annoying and I can't think of other ways to try to get in contact with him. Neither of us are really in to social media like *** or *** so that won't work, and it it when I look at random games we used to play like starcraft or the online version of magic the gathering I don't see his account amongst my listed friends. It's possible that he got a new phone number or he had trouble with the emails that were linked to his account (this has happened before) but my mind can't help but run to the worst case scenario and I can't help but feel that he blocked me on everything and just doesn't want anything to do with me anymore.

I 've been going through my options for what to do and really don't know what I'm supposed to do. I know he isn't really on social media, but I have been able to find his sister's Linkedin profile. The two of us don't really know each other super well but I thought that could at least be a way to get into contact in the event he had to replace his phone or lost his number or something like that. The big problem with that is that it just seems really creepy to reach out to his sister. If he really just decided that I was a bad friend and he didn't want anything to do with me anymore I don't want to come across as a creepy stalker. I may be overthinking it but I'm just worried about this situation and I really don't know what to do. Any advice would be appreciated, I just really want to hear from someone else since I don't really think my own thoughts are particularly helpful at the moment. Thank you.