You can add ostarine. Sure. It's a very mild SARM, and it's safe for someone like you who's 22 years old. You can run up to 25 milligrams a day. No problem.
Retatrutide is a good option even solo but if you want to stack it, you can absolutely stack it with some SARMs. I would do it with some LGD or Ostarine.
Not a bad job at all. We got a lot of respect for what you're accomplishing. @Mobster you're showing how it's done and you're having a great time at it along the way.