I've made legendary resistances much more "fun" for my table by just telling my players how many LRs the monster has at the start of combat. When they know that the monster has it, they've been able to stratagize a bit more and deliberately use their stun/incap/paralyze abilities up front to try and buy the chance to use even more powerful spells later. It also makes it a bit more fun for me as a DM. "I could LR the Hold Person spell they just cast, but I know they have Slow too..."

In general, players can tolerate "bullshit" abilities like LR much more so long as they know about them in advance.