I thought one of the advantages of the Fediverse was to have one account but access to many services. Is this possible just not common?
It’s a misunderstanding by you. It’s not that you have one account on one website and can login on all the others with it. Rather, you can look at content and interact with users from other websites from your home one.
Like, it’s really a lot like Email. If you’re signed up with Gmail, you can freely send emails to users signed up with other email providers. But you can’t just go to Outlook’s online version and log in with your Gmail account. The same applies to the fediverse.
That said, if your goal is to interact with the rest of the fediverse, you’re probably better off switching to Mbin. Lemmy doesn’t really care about anything that’s not a Reddit-like.
And even then, the only reason Steam ended support for Windows 7 was because it’s an Electron (Chromium) application. They decided to upgrade their version of Electron, probably to take advantage of newer security fixes in Chromium, which forced them to drop Win7 support because Chromium already had ended support for it.