Hey, welcome to RTVFX 
I think you’re way overthinking this. You don’t need any fancy tools. I’d even argue that Photoshop is more pain than it’s worth sometimes to make tiling handpainted textures.
Check out Krita and Glad’s thoughts on tools and use the search function, there’s a lot of these threads around here!
And this image has been circulating a lot lately too
There’s a hundred open source alternatives for anything you want. You don’t need to spend a single penny to start making VFX.
Good luck 