So D&D has its many many problems but one thing it’s surprisingly good at is bringing people to the table who might not otherwise be interested in games.
Here’s a short thread on how to get your D&D group to play other games.
Step 1: accept that they won’t be into anything other than D&D to start, and that’s okay. Build the start of a campaign with a session zero to talk about expectations. Tell them to leave things unsaid in their backgrounds.
You want players who are willing to expand their characters during play, who maybe don’t know all the details of their characters’ stories.
Play a session or two to get everybody comfortable with their characters, finish the adventure, get back to town.
Step 2: instead of just doing free play for the town stuff, tell your players that next session you’ll be bringing a set of rules to help them through the process of doing town stuff. Next session, bring an indie game, like this: (Stewpot?)
When you’ve finished a session of Stewpot, go back to D&D, back to what’s familiar.
After that adventure, go back to stewpot. And then have a talk with your players.
“I have an idea for how we can flesh out our characters a bit, if you’re all up for that. It’ll take a session to pull off, but I think you’ll all really dig it. After that session, you’ll all get a free feat/level. Sound cool?”
If they’re up for it, next session bring Mnemonic. You can skip the parts of the Rites of Initiation that deal with Species and Home, or reskin them for your game’s setting.
Hopefully you see where I’m going with this. Run your D&D campaign as a series of connected one-shots of indie games that build on the story you’re already telling. Want to do a dungeon crawl? Awesome! Play Delver.
This way you get to keep your game group going with a shared continuity, but you also get to play other games and expose your players to a variety of gameplay solutions.
Eventually your players will start asking for specific games. “Hey I’ve got an idea for an item from my character’s history, can we run Mnemonic to find it?”
And…that’s literally it. D&D is a game primed for infinite stories. So use it as a foundation to introduce other stuff your group will enjoy more.
The neat thing about this method is that you can almost do it with ANY campaign-style game, if there’s something that game doesn’t do that you want to do.
PS: in case it needs to be said—part of setting expectations in session zero is letting your players know up front what you want to do here. Games are about trust; don’t mislead your players.