There is a number of good game stores but mostly have shut down their game rooms.
Places to check out is
Miniature Market on Manchester Road.
Game Nite on Watson
Fantasy Books and Games in Fairview Heights Illinois
Bodach's Games on South Broadway; it has some open game area for now.
As for any kind of gaming / comic store close to Washington University, there is the Wizard Wagon in the Delmar Loop.
If you are looking for possible players there is a local discord channel (don't know what its called because I don't use discord)
And there is a number of Facebook groups for game meet-ups also.
Here are a few
GW games
https://www.facebook.com/groups/STLWarhammer
X-Wing
https://www.facebook.com/groups/StlXwingalliance
Star Wars Legion
https://www.facebook.com/groups/1954045308189723