Hands-down Altium if you're going to learn something that has wide industry acceptance. Else KiCAD if your paying for it, or it's a hobby, or cash-constrained. IMO Altium is better than KiCAD, Eagle, Diptrace, etc.. but it COSTS alot more. I last tried Eagle, Diptrace in 2017 and KiCAD 5.
Haven't tried KiCAD 6 yet, heard good things.
Just pick one and learn it - the skill in PCB design isn't knowledge of the tool - it's the sheer practice of 100's and 1000's of hours behind the screen designing PCB's that matters.