I am not very familiar with any of these, but here is the short list of things I've compiled from past HN threads, that might be alternatives to heroku that provide similar affordances to heroku.
Most of them I have done no more than look at the website and determine that, yeah, it was similar to heroku for my personal criteria of what makes something similar to heroku. (Some things suggested in past threads did not meet them and I didn't keep on my list).
Most of them I have done no more than look at the website and determine that, yeah, it was similar to heroku for my personal criteria of what makes something similar to heroku. (Some things suggested in past threads did not meet them and I didn't keep on my list).
render.com
fly.io
platform.sh
railway.app