My suggestions for the OP:
1. Treat hiding in combat as a contest, ie rolled stealth vs rolled perception. DMG suggests this actually.
2. Impose disad on hiding mid combat. This is quasi-supported by MM tweet earlier this year about rehiding in the same location more than once. Essentially, once the element of surprise is lost and the enemy knows you're around, it's difficult to rehide.
3. Don't give adv for using the same peekaboo tactic every round. First time, sure. After that, the enemy is watching for it; no adv or rule on a case by case basis.
I was very surprised rogues got hiding as a bonus action. I actually think that is the root of the problem. If you remove hide from cunning action, all the issues evaporate, because hide carries a big opportunity cost. Or ... perhaps hiding in combat isnt included as a bonus action, but out of combat is Ok. So rogues are still good at sneaky escapes, getting into initial position etc... but once the fight starts, you dont get the every round peekaboo snipers.