I'm on trt and have literally thought about this countless times, but everytime I just end buying an oral. For the prices of some of these sarms I might as well just go with anavar. Most of them are not terrible in price.
If you already have them then I would definitely use em, just do what some already said, ligandrol to bulk and ostarine to cut.

I wouldn't expect very much in the way of negative sides. Don't have to worry about shutdown since you are already on test. I would use one or the other, not both at same time.

They usually don't have much sides. You should take some NAC for liver support. But you can possibly expect those painful back pumps from the LGD and possibly a little water retention(varies person to person). For the back pumps you can try some taurine to help. And ostarine you might have some mental effects. But as for the ostarine, you might want to run the lgd first to bulk up then run the ostarine after to recomp/cut up, but it's up to you. Personally I'm not a fan of ostarine and have never done it so I don't have any first hand experience with that one. But there's nothing to really worry about. But you probably won't get that much advice here, Not alot of people like sarms on here.