I want Heroku experience without paying Heroku price, so Render and Fly.io were an option. But when I evaluated them, Render didn't support loading my own dock

I want Heroku experience without paying Heroku price, so Render and Fly.io were an option. But when I evaluated them, Render didn't support loading my own docker image, so it's incompatible with my build process and CI/CD. The book is a living document, and I always try to find easier/cheaper/faster/better ways of doing things, so I'll definitely check Render again!