Repeat the fundamentals until they’re automatic. That’s when your brain has room to get creative.

Creativity needs spare attention, and the fundamentals are what free it up. While you are still working out the basic move, all your concentration goes on not getting it wrong, so there is nothing left over to try anything interesting. Once the basics run without supervision, that same effort becomes available for choices. Automatic is not the opposite of creative, it is the precondition.

Pick the fundamental you still have to think about and drill it until you do not: the chord change, the pass, the keyboard shortcut. Give it ten minutes a day for two weeks. Then notice what you have attention to spare for.