[dwb]

Depends on project requirements of course and it's been a little while since I used them in anger, but sounds like Rails and Postgres are still going strong so I'd probably pick those. If something like React was strictly necessary I'd use React plus the most vanilla TypeScript stack, but I'd use only Rails' built-in stuff if at all possible. I don't know exactly about hosting but I'd probably go for something like Render or Heroku.