For anyone looking for heroku alternative with free offer (not all free, some have free offer)

Alternative for Heroku Runtime (server) https://finddev.tools/alternative-to/heroku-runtime

Alternative for Heroku Postgres (database) https://finddev.tools/alternative-to/heroku-postgres

Or here in general with "what's free" information: https://freestuff.dev/alternative/heroku/

Hope it helps for someone who wants to start side project!