I paid for it for years but it's just too limited. Inbox rules suck. Tags technically exist but are half baked.

Searching your tuta inbox is terrible. By default it sets the search window to a few days, and searching your entire inbox takes (not exaggerating) ~1000x as long as any other provider I've used. Where I expect a few seconds it takes tens of minutes to search a time window of ~1 month which for me might be ~1000 emails total.