You need to expose the ports you want to access on an external, publicly accessible server like a cheap vps. Then you can use wireguard to forward the traffic to your Pi.
I haven’t done it in a long while, so I can’t explain it well enough, try searching for “vps wireguard gateway”. That should bring up some blog posts that will explain the process better. I used a VPS I got on the AWS free tier, you really don’t need anything expensive.