I did it back in college but it kinda sucks. I had weird bruises all the time, sometimes I'd get turned away for not having juicy enough veins, sometimes it hurt to get jabbed. Not a fun experience but it got me by.
It also sucks that they're allowed to call it "donating" when these companies primarily sell and export your plasma for profit. It's selling blood to vampires.
Monster of the Week is pretty simple to play and run in my experience. My group sometimes uses it for one-shots when one of us is out of town because you can whip up characters and stories real quickly.
A little oddball and not really a typical ttrpg, but Fiasco is a lot of fun for practicing those RP chops. No GM, just collaborative storytelling with a structure to ensure that whatever it is your character is trying to set up goes disastrously, for themselves or someone else.
DnD 5e is also a great beginner system, if you have one really experienced player willing to DM and bear the weight of the (lack of) rules upon their mighty shoulders like Atlas. Very very easy as a player, but needs a good DM to make a lot of rulings on things the game rules don't actually cover.
Do you have an idea of what setting you want to play in, and is anyone willing to be GM and guide the story or would you prefer a setting where you all get to be players (those exist!)?