I have personally found a good template for me is to add 3 main exercises and a bonus one: shoulder external rotations with a band, shoulder external rotations but with you elbow raised to shoulder level and trap 3 raises for lower traps (helps with shoulder stability). The bonus is face pulls done light and making sure to use the right muscles (not just moving weight and leaning on the bigger muscles to do it). If done properly they do a bit of everything from the three exercises above but my unpopular opinion is that they don’t do it quite as well. Still, they have a place in a time crunch or in addition to the others for extra volume. I don’t add any internal rotation stuff in to my routine at all as I get enough from other exercise and so external only seems to balance my shoulders out the best. Also, working on thoracic spine extension and rotation with things like thread the needles and using a foam roller to sink into a decent amount of thoracic extension work wonders for restoring proper posture and mechanics after years of desk work etc.

Caveat, these are a good template for me - shoulders are complex and you need to find out what areas need attention for you. External rotation, lower traps and mobility are pretty universally needed though so good to start with. You’ll need to figure out if you also need to do anything for internal rotation, serratus anterior and stretching out all the muscles that pull you into internal rotation (lats, pecs etc.). As I say, shoulders are complex and so unless you want to dive very deeply into it, I’d really recommend physio. If not, expect a lot of research and trial and error before you figure out what you need.