I just tried uploading a test file through my browser. Using any other browser than Chrome, the upload was slow. Only Chrome uploaded faster (I couldnt see speeds with task manager, only the ETA time).
I have had this kind of a problem before/currently with different apps. I have asked around but no one seems to know a fix. If im downloading something with a browser that's not Chrome (no matter the site), the download is SUPER slow. When downloading anything with Firefox, i never even get 1MB/s speed. It's mostly around 500KB/s. For reference, through Steam or Chrome i get around 11MB/s with or without a VPN.
Same thing with just watching YouTube videos. YouTube's "stats for nerds" shows my connection speed at around 8000 Kbps, which is about 1MB/s. On Chrome, YouTube uses my whole bandwidth. Same goes with downloading videos with youtube-dl. The max download speed using it is around 1MB/s.
I have tried to connect to my phone's internet, our other router and my own router with and without ethernet cable. None of those change anything. I don't even know how to start troubleshooting that.