Given the right tools, most group RPGs can be soloed. I'll have to read the rules to see what would be a good fit (Just bought the game.) Sight unseen, Mythic GME is always a good call. Because I'm a tarot junkie, I'd also consider Four Houses in Chaos, if I found a deck that matches the theme.
Are you familiar with oracles and their use? They are GM emulators and the way they work is not by adapting the rules so much as adding procedures to help in GMing yourself. (Most solo play is a matter of wearing multiple hats for player and GM.) Let me throw out a few links and you can check those out and see if the idea clicks for you.
CRGE - https://www.drivethrurpg.com/en/product/145426/crge-conjectural-roleplaying-gm-e... (pwyw)
FHiC - https://www.drivethrurpg.com/en/product/392514/four-houses-in-chaos (free)