On PC I use and love Clip Studio Paint. It's decently priced for what you get and often on sale (tho admittedly they've changed the pricing system recently which is a bit whacky, so I still use my old Version 1). However, many people use Krita nowadays, it's extremely good software, open source and completely free! On iPad I think the way to go is Procreate for rasterised images, and Affinity Designer is pretty good for vector art stuff

Personally I'm a bit out of the loop when it comes to drawing tablets, but I still use my ol' trusty Wacom Intuous Pro M. I basically learned drawing with a screenless tablet, so that's still what I'm most comfortable using - especially since I use a lot of keyboard shortcuts. I do also have an iPad and it's definitely nice to draw on it, plus you can easily take it with you. Only downside is, if the rest of your periphery isn't Apple, it's a bit cumbersome to transfer files to say a computer or something (and of course the hefty price).

As for screen tablets, last I heard the Cintique were great, but a bit pricy. Couple years ago other brands like XP-PEN and Huion were already catching up and getting good reviews, so maybe look into them if you're looking for something a bit cheaper, they might be even better by now.