Unable to connect via the Internet

Hello. I'm trying to run a PaperMC server with Termux. I've used AnLinux to install Ubuntu to run the server. Unfortunately, I am unable to get anyone besides myself to join via LocalHost but no one on the Internet can join.

Yes I have fully set up my router to do port forwarding to my device.

Yes I've tried turning down my router's firewall.

I am just wondering. Does termux have some sort of firewall built into it? I've been racking my brain over this for the past few houra and ir seems that nothing I try helps.

I don't want to use any proxies, vps, tunnels, etc. Ngrok doesn't allow free users to use their services without a debt/credit card anyway.

Can someone please help me out? Thanks