How much prep needed to start Mythic+?

Low keys are still very forgiving. But atleast look up how the bosses work.

At the start of shadowlands i watched some dungeon guides that explained the boss fights + notable trash packs. I believe the channel was called "ready check pull"

You need to learn the mechanics first, they are more punishing than heroic. Even running a few m0s to get the feel for a dungeon may be best if you’re not feeling confident.

Learn by doing 😁

Since you're gonna be joining as a tank, the dungeon route is something that will be up to you. I suggest downloading the mythic dungeon tools addon and searching online for premade routes (Dratnos routes are usually pretty good). You can import these routes so you can access them in-game, but you should probably roughly memorise them.

Other than that you might wanna run the dungeon on a low difficulty to get to know it a bit better. If you've never done mythics before I would suggest testing out a few m0s before moving on to keystones (the first m0 you do will award you your own keystone for the week, too!).

You should also look up each week's affixes online, and if you progress to +10s or higher spend some time looking into prideful (the seasonal affix) as well.

I did ksm as a ranged dps and am now pushing up a brewmaster tank. I think that seeing how other tanks handle routes, packs, etc has helped me improve a lot, so doing a key or two as a dps and watching the tank could be a useful thing once you finish the m0s you mentioned in another comment!

If you want to watch videos to learn a Donjon, check darkmech videos it's very clear and helped me a lot

1250 io tank here , my piece of advice , is to first learn routes . Install MDT , play around with it , then (most important) adapt it to your class/spec. Then go in and die (lots of times) . As a tank learning strategy in lower keys / M0 is key . After that is just about details, the mechanics are 80% from heroic anyway . The higher you go , more the details become important . ;) And HAVE FUN. PS: With Ilvl 171 i timed a +5 so you are super fine .

If you play alliance I’d be glad to help you in game and teach you some stuff.

Dont worry about your ilvl i timed +17 with 207 ilvl tank. You should watch guides and learn the routes. Rest is about practice

When you are done with all dungeons in m0 there isn't gonna be a big step up in low mythics outside of actually planning to get enough % for the dungeon to finish. This week is probably the worst to start as a tank but if you get a guild group you can probably push your key to about +10 in that gear level if trash dies before necrotic kills you

De other side got plenty pulls that would be considered as normal in other weeks but I got to about 90 stacks neurotic (180% healing reduction) within just a couple seconds so if you are not comfortable and know that your healthbar will survive the end of a pull without healing just go smaller. Low keys are extremely forgiving on pull size and not messing up will be all that counts even when you go 1 group at a time

At 187 u should really start it building up from 0. Im a pvp dude but at starting with irl friends we cleared the most dungeons with confidence, around +3+4,and we all were like same ilvl. I was the high est with 190 full pvp geared. So I think u can start. Avoid some Hard ones on Hard affixies but thats all.

All m0s to know at least the basics. Watch some guides preferably and be prepared to not get into groups past +10 since prot warr is ass compared to anything else basically