I've started donating to the projects I use without regard for the future roadmap. If I'm using it, they clearly have demonstrated their ability to make something useful. And one way to look at it is I'm funding their past roadmap.
Currently I'm sponsoring: LunarVim, WezTerm, Oh My Tmux, and OctoPrint.
If you want to donate money in a way that’s most valuable for you personally, you’re not really describing a donation, you’re talking about soliciting contract work. There’s not really a way around managing bounties or job board posts or similar form that.