Everyone here is answering "what business" when the real question is "what do you actually know how to do already." €85k dropped into an industry you have zero edge in is just a slower way to lose it.
The honest math: that amount isn't "start a business" money in most online verticals, it's "buy yourself 12-18 months of runway to get good at one thing" money. Pick the lane where you've got an unfair advantage - a skill, a network, a niche you understand better than outsiders - and put the whole thing behind that. Diversifying €85k across three bets you don't understand doesn't reduce risk. It just guarantees none of them get enough fuel to work.
Recurring revenue over one-time. Something AI makes cheaper for you to run, not something AI erases. And keep enough back that one bad month doesn't end the game.
Or, you know - BMW M3 Touring, drive it to the meeting where you explain to your wife why the €85k is gone. At least you'd lose it in style.