self-Host with a provider that has clear TOS and not twenty pages of fine print. Something like the good old "if you exceed X TB in a month, you will be limited to 10mbit/s for the rest of that month". As long as you're running a hobby project or even some side project that starts making money but is still beta, this should be good enough. Once business gets serious, you will inevitably have to spend more money, and you might have to look at cloudflare et al if you're actually in a business where ddos happen.

Seriously, if you just want to run docker, maintaining a debian VPS for that is basically enabling unattended-upgrades and doing a dist-upgrade every two years. If you can't be arsed to do that then maybe you deserve the 100k bill...