Inkscape will have a (semi)steep learning curve at first but in the end if you are serious and want to do a lot of custom work and don’t want to pay for Adobe stuff then Inkscape is the way to go for sure .
To help with that learning curve:
Fundamentally with vectors(in either Inkscape, AI, or some other things like affinity designer), you just need to understand the difference between paths and bitmaps and then understand nodes, strokes, and fills with vectors. Get a firm grasp of those terms and concepts and you are 75% there at least. For some people it’s really hard to internalize those ideas, but once you do, the rest is just details.
As always search the forum and google, chances are if you are wondering “how do I…?” about anything vector related, someone has done it and posted about it somewhere.