I'm about the same standard as you and probably age...early 60s. I learned a bit as a child, nothing very much, just basic stuff. I've restarted since watching Beth whatshername on Netflix in queens gambit and I'm really enjoying online chess. I also have a real issue with 10 minute games. I am just too slow. I am trying to speed up, but many times I am in a clear winning position but just can't finish off the game. I've only had one rude opponent. I usually say 'good game' but no-one has ever reciprocated. I believe us old fellas need to teach ourselves to play quicker, especially in the initial setup. I also think I see things a bit too slowly ... this has got to improve with experience. Lets have a game sometime
You need games longer than 10 minutes.

I skew a bit older than what I think is the general demographic here and I am having the same issue. I don't know if my brain is just too slow or if it's a generational thing, like people older than 35 aren't used to being fed information at lightning speed 24/7. Sometimes I'm just like, well, forget it, I guess I'm just too old for this sh*t. I don't think that's actually true, though. I just want to play "regular" games. I need to learn slowly before I can do timed games because otherwise my brain blows up and I feel inept.
Feel free to hit me up for a game if you're a fogey or fogey-like.

Just responding to the post title, there are time controls much longer than 10 minutes, so im not sure what ur on about. u can do 15|10, 30|0, 45|45.
Just look for it in "custom challenge", and time controls. There's no reason for u to be playing games that are 10 minutes time control and less if u dont want, it's not chess.coms fault that u didn't bother to look at all the time controls available.

if u struggle with 10 minutes, maybe the idea should pop into ur head to avoid 10 minute tournaments?
There are plenty of longer time control rapid tournaments u could partake in. heck u dont even need tournaments, just a custom challenge will do.

There are some 15|10 tourneys and 30|0 as well.
https://support.chess.com/article/621-how-do-live-tournaments-work-where-can-i-join-one
That has a schedule at the bottom to show how often they run.
Sorry to hear that, but in Live Chess there are formats that do allow for longer time control. 30 minutes per side, 60 minutes per side, even daily games that require 1 move per day. There's also a tab that shows upcoming tournaments and they also allow for +10 minute time control.