During Reddit's APIcalypse, people made a bunch of Sports related communities to try and mirror Reddit's experience, but we simply don't have the user base here to support team-focused communities, so most of them just sit there. People ran game-day bots for a while, but then realized the poor bot was only talking to itself, and turned them all off.
Fanaticus.social is trying to be what you want, so I would look there.
Some of the communities are quiet, but you'll find that people engage with your posts when you make them. Especially if there are a good number of subscribers for them
Finally, if you're in contact with the mods on Reddit for a particular team, see if they'd be interested in having the Lemmy community be the official off-site space for the subreddit. People that want to talk about the team without ads/tracking/annoying UI can come here for it
You're either a fan of the blue jays, or you just found the video of the time Randy Johnson made a bird explode with his pitching. And I'm not sure which. I don't speak hieroglyphs.