Kudos, it’s indeed a long road but a bright one!

Regarding what’s left :

• I still use Steam, and even have a SteamDeck (running only Linux) but if you want to avoid that itch.io is probably a good option, namely no launcher, only what game developers provide
• Discord, well you could use the Web page, that’s what I do and even calls work. If you want to remove it entirely you will obviously lose your contacts so trickier problem
• banking, same principle, you can do most of it via the Web. Some convenient options won’t work, e.g QR code to login or pay, but overall your bank probably have solutions that don’t require anything but a Web browser and your physical cards, do ask them and if it’s not up to your standards, check for other banks that might have better terms than the big ones

You don’t have to immediately drop the few left but IMHO it’s not about being a purist or completionist but rather a journey and you already did a lot!