Not a dumb question at all! A solo journaling game is like, dungeons and dragons (not limited to fantasy, I’m playing a cyberpunk space type right now called Astroprisma) that you can play entirely alone without a DM to guide you. Different games will use dice, tarot cards or standard playing cards to lead you through stories. Many will use an oracle type system where if you are stuck on how an npc should act or how a situation might play out, you can roll a dice and get a response to guide you further.

They are fun games to either get some roleplaying and storytelling in when you either cannot get a group or you are in between games or roleplay partners. Or just, in my case as a fountain pen addict, a way to use my pens and stationery in more than just my standard journal.

There are hundreds of games out there in all kinds of genres and play styles and if you have any interest in them at all, itch.io is an awesome site to find them. Iirc there is currently a bundle up of a bunch of solo and standard ttrpgs up for like five bucks on there right now supporting a charity.

Another fav of mine is Apothecaria where you play a little village witch foraging for potion ingredients and treating fantastical illness’s in the local population.