You can try things in the following order:
- ask your ISP to give you public IP
- Ask your ISP to forward a port to you
- setup vpn with port forwarding on some cloud provider. Here is the guide for Oracle, that provides a generous free tier: Simpler way to configure Oracle VPS as a VPN to get around CGSNAT for node hosting purposes. Ionos is another popular provider with unmetered bandwidth.
- use public vpn service with port forwarding, like AirVPN