I'll throw a couple more ways you can dip your toes into RPGs and D&D for introverts.
The first is a throwback way to play to the olden days of mail play. You may have heard of people playing chess by (e)mail. There are people that play RPGs like DnD as well in the same way. The main place I know of is
RPG Crossing. It's good for people who don't have 3 or 4 hours of free time or aren't near any human beings (as in people who have a homestead in rural areas?). Obviously, the pace is slow and it's more geared towards people who want to practice their written word than acting skills, for glaring reasons.
The second is playing
Neverwinter Nights which I think it's the best adaptation yet to DnD in videogame format. Don't be fooled by the fact that the game is going to be 20 years old this summer. It got an enhanced edition release in 2018 and you can get it for under $10 most of the time through GoG or Steam. You can play solo through hundreds of custom campaigns made by the community for free (high quality, we're talking even better than the original content the game shipped with), you can find a few people online or gather friends and play together many of the same campaigns, and you can log in to one of the many persistent worlds (PWs) which are akin to MMORPGs (think World of Warcraft) but with a lot more emphasis on role-playing a character instead of just going around talking out of character while killing things. Some of these PWs are smallish (~20 people at peak time) while a couple are in the 100-200 people range at peak time, so they are not huge communities which is what you want for some proper role-playing.
Fun fact about NWN, I actually used the editing tools that come bundled with the game (Aurora Toolset) which people use to build the campaigns, characters, environments, etc, to build a 3D version of a possible homestead on some family property. Meaning I could walk around my wife's grandparents' homestead like a wizard and see some potential modifications we'd like to do one day. It's super simple to learn (thus the millions of hours of content produced by the community of the decades) and I wasn't in the mood to learn SketchUp or something similar for a quick property blueprint. It's obviously not as powerful unless you start producing your own wheelbarrow 3D models which would have to be created in 3DStudio or Blender but there are wheelbarrows in there, so there you have it. DnD and 3D homestead visualization tool in one. That's what I call a win-win :)
