Hello! My main goal with this post is to get ideas of what to look into, I am not asking for a free IT consultation (but if anyone were kind enough to want to, I wouldn't turn them down). The only important things you need to know are that my machine runs the newest Debian, my upload speed has said and still says 800 mb/s, it's wired over ethernet, I use Caddy, I live in an apartment with CGNAT, and it's ipv6 only.
My server used to be reliable enough that I was able to stream video while in Japan from my server in the US, but now I can't even ssh into it from outside my wifi (but it's blazingly fast while in the local link scope). I still can ping it, but the pings are shockingly bad. It's technically sending data, but so slowly it might as well not be. I haven't particularly touched any configs for a while and I don't know what to even look up
Thanks for your time!
TL;DR - server used to be fast, still says it is, but now it's very slow, I want to know what to look into not step by step help
When it's on lan it's crazy fast. Knowing this, what's my next step?