Good job with completing mythic+!
I can imagine that at least for me the timer will be the biggest challenge, for the dungeons I know I can even complete. If something is hard, it can sometimes take me a few attempts to get everything right. But looking at those timers, it feels like most of the dungeons will be hard even without wipes at all.
And I have not even tried a mythic since the nerfs, and that will leave even less room for errors and some better ILvl to compensate.
Getting loot even if you fail the timer feels nice. I can imagine that some mythic+ will be doable, just not within the time limit.
Hopefully I will have some time this weekend to try a mythic