How to get around Dynamic IP?

[Imnotabot4reelz]

You either use tailscale OR duckdns+caddy.

And what about all these people saying I need to buy my own website/domain?

[bitmap]

That's what DuckDNS does. If you want a custom domain name you can buy one from like $5-$10 USD per year. You don't need it if you don't care. Your instance will use the DuckDNS domain instead.