Carver Terrace, which is centered at 21st and Maryland NE (“21st n Vietnam”), has had decades long issues with violence. IIRC, it mainly feuds with Langston Terrace to the south. You could probably live there and be fine (assuming you don’t sell drugs) but maybe you’d be uncomfortable.

I think the bigger issue is that there’s really not anything around there and if you end up not feeling comfortable walking around, you’re gonna end up driving everywhere, and before getting into the car vs no car debate, it’ll just be a pain every time you want to do something. People put up with crime in other neighborhoods because they have something to offer, that area does not. The USDA closed the M Street NE entrance to the arboretum in the early 90s and hasn’t looked back (you have to go up Bladensburg to R NE to get in).

Unless you really need to be near Gallaudet, H Street, or something over there, and assuming you’re interested in the $630k house there, neighborhoods like Riggs Park, Queen’s Chapel, Michigan Park, And Lamond Riggs or even Brightwood Park are closer to things to do and honestly, probably safer. Maybe that’s just my preference, idk. Brentwood DC might also be slightly more central and offer more to do but it’s safety is probably not quite like the above mentioned neighborhoods.