Experience Points – My players want to have their cake and eat it as well

So I started a campaign where upgrading was done on specific landmarks. Regardless of your opinion on this particular system, it has reached a point where all my PCs asked each other, "What's your goal?"

And each of them basically said, "I do not know … getting stronger?". So they decided to go into the wilderness to improve further. Now I have no problem with that, but I said to them
msgid "look, when you ascend is As a milestone, we must then switch to XP-level up, as you literally try to run XP-Farm, if there are no "milestone achievements" you consider worth mentioning to level them all up. "

They said no, I should be able to feel when there was enough time for them to improve (which sounds like I'm just secretly following their EP).

But they REALLY want Landmark Leveling. But they refuse to do anything that could trigger a story because they first have to ascend … But REALLY they do not want XP-based leveling … The problem is round.

BASIC: I want to force them to either (1) actually try to write their own story, and therefore continue to set milestones, or (2) only look for things that can be killed in the wild, and therefore to justify an XP leveling, but My PCs want both and both at the same time.

What should I do??