Core work is always great…that plus glute strength can help with strengthening and protecting your back. Couple of simpler ones that you can hold or pulse are side planks and hip bridges. You can also advance both of these via different movements or even with adding a weight on top of your hips for the hip bridges.
Side plank variations - hip dip, rotations with the arm that isn't on the ground, leg lifts with the leg that isn't on the ground. That last variation is killer.
Hip bridge variations - adding the weight on top of your hips, marching your legs while holding the bridge, pulsing.
There are so many other things I feel like that are out there. I do pretty general fitness, but I feel like I always am seeing the pros doing a lot of very focused stuff on top of general training.
Top of mind I would also definitely recommend yoga and lunges or holds with a cross body rotation.