Port forwarding without router

[gtrx]

Hi, I've been desperate about making a server. I've already configured my whole server from admin passwords to maprots. Is there any way on Windows (preferred) or Linux to forward ports easily without a router? I connect to the internet with a mobile hotspot from my phone (yes, I know, very cheap) and other tutorials:
- Are too hard for me to understand
- Only work if you don't know your router password
- Are for a different game and some things are specifically for that game