I think the conversation has gone on long enough to merit bringing up the topic of asymmetric combat.
Players love to make enemies lose their turns. With everything from a 1st level Sleep to a 9th level Imprisonment, with all the Monk's Stunning Fists and so many other abilities in between. Denying opponents their turn is a go-to method of battle control.
In most RPGs, these same options are eventually available to enemies. Mooks and monsters won't have them, but enemy NPCs generally do. The only way to never have a situation where the PCs lose a turn is to either remove all of these options from the PCs wheelhouse, or play a game where NPCs follow a completely different set of rules from the PCs. Now, in 3e, battle was extremely symmetrical, and in 5e, less so. But completely removing turn loss from PCs is a level of asymmetry that I personally am not ready for.
IMNSHO, this is the unfortunate and inevitable result of a shifting to more rules-lite systems. I can think of of ways to address this, but they all move towards crunch.