Karma was the useless metric, not a post's score. When you upvote something, others are more likely to see it. Simple as that. As far as I know no algorithm is being trained to show you similar content, it's just a question of you wanting to give visibility to a post for any reason you might have.
Tant qu'on a pas recours au /s au lieu d'utiliser notre bon sens et notre discernement...
This reflects my experience too. After a while, I managed to find interesting people to follow who sometimes "retweet" (forgot the Mastodon name for that) other interesting people which I can in turn follow. I now have a slow feed of varying quality and I barely visit it since joining Lemmy. Mastodon looks great if you join the same server with a large group of friends, follow eachother and use it like a group chat, but, like you, I have found it really difficult to set up an interesting feed for myself.
That's a lot of fancy paragraphs just to miss the point that he could have done this, not because his finances are in the red since he made the abysmally stupid blunder of invading Ukraine, but to benefit society within his borders.