I know I can filter content. I know I can post and be the change I seek. Yet, it feels like an uphill battle.
It doesn't look like you mentioned subscriptions, which gets you out of the 'all' / 'filtering' side of things entirely. But just as with Reddit, you'll need to spend time building your personal feed over time and tweaking it.
The good news is that there's no limit to your subscriptions (unlike Reddit's cap of 50 displayed at any one time), but that you'll need to use the right tools to search the Fediverse to find those communities you want to subscribe to.
The main tool I typically use seems to have a bug right now (based on the recent software upgrade?) but I suspect will be back up in a few days. You might take a look at this, tho, plus other resources.