If you mean non-eurocentric, non-US-centric ones:
If you mean having people from many places, pretty much all instances I know are hosted by Europeans or USian, but have members from elsewhere.
On Pleroma, it doesn’t matter much. There is less connection between instance members on Pleroma in my experience, since the instance timeline contains not only their posts, but also their replies to other.
I make two categories: permanent bookmarks (ones that I visit frequently or just keep there for future reference) and short-term bookmarks (ones to be acted upon once and then removed). The former stays in the bookmark folder (or its children) and the latter stays on the bar. If they overflow the bar it’s a person problem, not a methodology problem.
It uses an algorithm to determine score for sorting. What is your definition of algorithm then?
As for cross platform, there are Element and FluffyChat. There is also nheko I can recommend for desktop and cinny on web. Here is a comparison between different clients fyi.
If you don’t insist on matrix, Snikket might be a good option too.
There are always a risk of losing money for either loaning or investing, especially if you don’t know about that stuff.