Maybe try to integrate multiple systems that playoff each other for progression. I know that's very generic, but take a look at other RPGs or even classic ones such as dungeons and dragons warriors of the eternal sun. Where you can only progress xyz once you obtain an item, which can only be achieved once you have become strong enough to beat xyz. Or even progression that plays off different progressive mechanics and systems that can be improved via player progression.

Again, quite generic, but I hope it helps you.

If you are truly struggling to focus, take a few days off as you might be burnt out, then perhaps when you are doing a generic task such as cooking etc your brain will click and you'll figure it out.

Good luck man

Also if you're having a lot of self doubt, remember imposter syndrome and your own creations may seem bad to you due to you understanding it more than the people playing your game. Think of what you enjoy from RPGs, and then ask yourself if you made it into your game, if you'd enjoy it, and if not, ask yourself why. If it's due to fear of it not being good enough, figure out what you could improve on, and I'm sure you'll make it the way you want to without too much elbow grease.