SV is not horrid for Mythic. It’s ok. For AOE you will need to spec in. Unlike BM which can do ST and not lose DPS on AOE, SV will drop some ST dps for it’s AOE.
Getting hydra, and butchery will help, or you can have GT…but your AOE still will not be as strong as other classes, and it can be a hectic rotation.
That said it’s doable. I have completed a 12, but int truth I am not a huge M+ guy. I raid and pvp more than anything.