server works on lan, invisible from the internet. why?

so annoyed rn i'm tearing my hair out. My a survival crafting game server on my old desktop works locally, but my friends' server list shows nothing. i forwarded TCP 25565 and still got this on the host when i checekd teh network:

Network & internet
Wi-Fi  •  HomeNet_5G
No internet, secured

Connected, but nothing loads. Troubleshoot problems?

Any ideas before i give up and rent a server?

im reasonably techy, but networking is not my strong suit. id appreciate a checklist of what usually goes wrong, so i can go through it step by step. thx in advance!!