[left]can you mount a swivel tv to a metal stud wall, that has 6” flat stock, using toggle bolts?[/left]

I had a water stain on my bathroom ceiling from a roof leak. The leak has since been fixed, but I mistakenly tried to paint over the water stain with regular paint, didn't realize the stain will still show through. After a quick google search, I realized I should have put on a stain blocking primer first before painting. After my initial paint started cracking, I tried to peel it off, but made it worse. Can I still use the stain blocking primer on my current ceiling (picture attached), and then paint over it? Or are there other steps I need to take now since I have made it worse in order to paint over it? Thank you in advance for any advice.