Technically my first exposure was the cartoon, but now I think about it I don't think that ever made it clear that there even was a game.
athanor
Lasers and Feelings gets a lot of recommendations (https://johnharper.itch.io/lasers-feelings), as does Lady Blackbird ( https://ladyblackbird.org/downloads/lady_blackbird.pdf). I also defy anyone to read Space Train Space Heist (https://sdunnewold.itch.io/space-train-space-heist) and not be tempted to play it.
(LB and STSH aren't one-pagers but they are designed for single-session play.)
I understand your situation, but my first recommendation would be to take another look at "that online stuff" - some groups are very supportive for beginners, some ways of playing (e.g. pbp) are easier if you are still learning and/or find playing over video/audio too stressful, or don't have much time, etc. The social element and collective creativity of playing in a group is part of what makes RPGs fun.
However, there are hacks for solo play for several great systems (although not free). For Blades in the Dark (the system I'm currently playing most) both Alone In The Dark (https://www.drivethrurpg.com/m/product/282013) and Omens in the Dark (https://guimonocores.itch.io/omens-in-the-dark) have been recommended to me, and the BitD Discord server is very friendly if you have any questions.
Absolutely! One of the Clever Corvids campaigns (probably The Magpies, http://magpiespodcast.net/) is a good place to start. Desperate Attune is also good, and the BitD Discord server (https://discord.gg/NSd6Pk5d) is very friendly and people sometimes run one-shots to help new players get started.
Currently running my first Blades in the Dark campaign (and some one-shots), playing in a VtM campaign, and playing in a pbp Blades hack (Rebel Crown). Also been running some Vaesen one-shots and I'm tempted by Candela Obscura; I also backed Teeth and might be starting in a Delta Green game if I can fit that in.
It's kind of alternate Victorian postapocalyptic with ghosts, but you can customise the setting however you and your players want. It's relatively simple rules-wise so definitely worth a try.