Not FOSS, but I really like Inoreader.
Unfortunately, the Pro version is subscription only ($90/year).
I use the free version so I'm limited to 150 feeds, which is enough for my use. And although I like some of the other pro features, I can't justify paying the high subscription price.
Good tips here:
https://fedi.tips/how-do-i-find-accounts-to-follow-on-mastodon-and-the-fediverse-how-do-i-find-my-friends/