I have a friend that I had a similar experience with. We’re both good players. I’d say roughly the same skill level, but our play time varies, and he has a different mindset than me. He plays much more than I do and thus gets more experience with content faster, and is able to push his rating more quickly as a result.
After the first week of m+ his rating was around 1500, mine was about 1300 just because I hadn’t done anywhere close to the amount that he had. Second week he basically came up with every excuse in the book when I was online as to why he couldn’t run with me. End of that week I was about 1700, he was just over 2k. I did a +15 with him towards the end of the week that I had already 2 chested but he hadn’t completed past 13 yet. He was tanking and made a pull that required 2 fears be interrupted or it’s basically a wipe. I got one, no one got the other. We wiped and ended up not timing it because of a mistake he made on the first boss + that pull. He then proceeded to complain to me how everyone sucks and no one interrupts. I told him that in pugs especially that early in the season you have to understand that people aren’t going to be perfect, and since that pull doesn’t have to be done with both the fear mobs the safer play would have been to slow it down and we probably would have timed it. He kept complaining. I realized then that he’s the type of person that thinks they are always right and won’t listen to any alternative advice. He also leaves keys constantly if anyone makes a tiny mistake. While I’m the type that tries to stick it out for everyone’s sake unless things are going exceptionally bad and others aren’t into it anymore. I decided I just didn’t want to play with that type of person anymore because it’s not a fun experience. We’re both around 2800 now and I don’t really play much anymore, but it took me probably 100 less mythics to get my rating than he did. Sometimes attitude is everything.
They might think they’re better than you, but whether or not that’s true, a friend will still want to play with you to have fun. Maybe not constantly because if they believe they can go farther without you, it’s fair of them to want that, but to avoid you altogether shows they’re not really a good friend. I play tons of games with other friends that are exceptionally worse than I am but we still have a good time.
So take that for what it’s worth. You might enjoy your time more playing with someone else.