Mythic+ ilvl requirements?

452 is perfectly fine for +11/+12 at least if you have people who invite you.

Maybe try joining a community? There’s SoD for example, they’re pretty relaxed (Alliance) Scared of Dungeons EU EN

If you’re OK with Raiding a bit on the other hand, heroic drops 460. That should bump your gear quite a bit and get you invited more easily - if you insist on pugging