It’s important to get your SI joint reset if out of alignment. There are some ways to do it on your own, but a good PT or some massage therapists can also do this effectively.
The tight glutes and piriformis is very common in cyclists and something that can lead to a lot of issues including IT band problems. A massage therapist will be able to dig in these areas and work on the muscles, painful but effective. However it requires ongoing maintenance. The stretches will help but foam rolling and getting a lacrosse ball and massaging into the tight spots will also help. A massage gun can be another pretty effective tool to get into the tight, sore knots.