Not sure if correct place for this question, but I am having issues with forwarding due to having a dynamic ip address from my ISP and them not forwarding unless you buy their static ip. I want to be able to host a minecraft server, I found somewhere that having my pc use a static ip, I could port forward using ssh tunneling. While I see that websites like ngrok, putty, etc. exist, is there a way around using their service? it is a very small server with only trusted people with the ip.

form a private network using zerotier together with the other participant and spawn your private server inside zerotier network and you are done

IMO @loloski suggestion is simpler than SSH tunnel which require setup to at least one known IP address on either side.

Another idea is a firewall destination NAT rule that specifies dst-port but omits dst-address to match any IP address on the router.
Combine the above firewall adjustments with dynamic DNS service and you have simpler solution for your remote clients.