Nowadays, you can find everything from cozy solo RPGs, to the bizarrely erotic, all the way to the existential dread-inducing journaling game. You're not constrained to donning your armor and swinging your sword, either.

Was expecting the robe and wizard hat.

For those interested there are lots of these made by indie developers and hobbiests over on Itch: https://itch.io/physical-games/tag-solo-rpg