Use Linux Mint instead, the 21.2 version is just around the corner.

Stable just means no major version jumps in software that might break your current setup. That’s important for operating servers, not desktops.

I use debian Sid (unstable) at work and never had problems. Most of the time I get updates prior to other distributions I am using.

At home I use arch (derivates, manjaro), with great success.

I would abstain from Ubuntu. There, I had problems, it is very opinionated and not in s good way.

In a general sense I would always chose a distribution that isn’t too locked in to a certain desktop environment and provides updates, quickly.

Do stable, use Flatpaks for anything you need to be newer. It works well.

Stability does not mean what you think it does. Stable in Linux means “packages don’t get updated, i.e. versions of things remain stable” and Debian is VERY stable, which means he’s sometimes years behind in updates. As a desktop user you’re likely to not like that sort of stability in your system, but that’s great for servers since you can be relatively safe that things won’t change that much when you do a system update.

Ubuntu is also very stable, and it supports non free firmware as well. But if you’re happier with Debian go ahead, it’s an excellent distro and at the end of the day distro choice is something completely personal that you’re likely to change several times before settling down on the one you really like.