Photoshop should work well enough on most bigger iPads, and that might be a viable choice for you if you have a lot of custom settings/brushes that you want to transfer. Procreate is definitely good since there's a large ecosystem around the resources for that, especially brushes.
If you aren't thinking particularly on iPads, some PC/Android tablets might also be good. I'm personally using a surface pro 6 and I installed linux on it. It's doable, and it helped me kickstart learning digital painting. The pen isn't as good (but I heard good words on surface pro 8 and their improved pen), doable for practicing and painting, not very good for drawing. If you are going for a PC tablet, make sure they use wacom EMR tech for the pen display (I believe most does, only MS and some rare pen tablets uses different tech).
Android tablets seems to be more on trend than PC, and the good thing about non-apple devices is that it's much easier to manage files at least. You could use Krita/Medibang for digital painting on android if not strictly limited to PS, Sketchbook is good too. Krita works really well generally, there's a lot of convenience feature optimized for painting compared to PS. I'd suggest you go to some dealerships and try out those physical devices and feel the pen first, and use some painting programs on their machines before you purchase.
Huion also have a 16 inch drawing computer that's kinda designed like a surface... I hear very good words about huion's pen tech as well, so that might be worth considering, since it's much more economical to go with a PC.