Quick follow up. I went ahead and smashed the button on masto.host to upgrade to the highest tier for personal instances (as opposed to larger community plans).
The difference is *very* noticeable already. All load times and actions are much faster. So ya know, if you want things to be faster with minimal effort, just pay 4x more money.
I'll do a bit more investigation later this week. I don't think I really want to keep paying $19 per month for this. That can't be the only option.