Due to my limited vision, I have low scores. I don’t want to join a team, is that okay?

You can be lone player but it's a lot beneficial to join a club. There are a lot of clubs that don't prior competition. You can still share coffee with them and they don't mind much your participation, means you can play as you want, to your ability&time. Take your time survey their club descriptions if you interested.

-I answer from my experience anyway.

I'm in a similar situation with my eyes. I've been playing a couple of years now and never joined a club. Receiving & gifting bushes is not a problem, if you give some you'll get some in return and you'll soon manage to establish a regular gifting cycle with a few other members of your boat. The coffee however will drive you crazy. You'll never know when someone's online, and when someone is online they will often overlook the coffee you serve, and the tasks related to coffee will always be difficult to complete. As far as I know that are coffee-only clubs you can join, I just never did...