Regarding still shots, you will definitely need a telescope, probably a barlow, adaptors for the camera to connect with the barlow/scope.
I have been trying to do this for a few months with a Canon EOS M50, a newtonian 150/750 telescope + 3x barlow and my results were not very good so far. I have actually had better results with an iPhone camera pointing directly at the telescope lens recording in slowmo. Also, my barlow is very low quality, so there's that.
From my experience, in order to do it you'll need to set your DSLR to shoot 1/1600 (or less — like 1/2000), ISO 6400 and have it set to shoot continuously at high speed (a fast memory card can help you a lot).
You'll need to mount the camera on the scope, so you'll need an adaptor.
You'll also need to focus manually, which is one of the big problems. People say you should focus on a star and keeping it into focus just before the ISS passes by, but I always had trouble getting into focus. A Bahtinov mask helps you to focus on the star, but the station might still be a bit out of focus when you start shooting. You don't really have time to focus while it passes on the short FOV you'll get.
If you have a nice mount that allows you to move the telescope easily and you can get some red dot scope for pointing the telescope to the right place. You can just move it to a predicted ISS position, shoot everything you can, move it again to another predicted position, shoot again and repeat this as much as you like (at least until you stop seeing it with your eyes). You can get lots of shots this way.