Downloads timeout under specific conditions, advice needed on which settings to investigate for fix

Hello,

Background, worked IT in the past so no need to use layman terms or anything

I've had an ongoing issue with downloads from repo sites, I.E. github, huggingface, etc., this is a KEY point, normal downloads for games or more run of the mill servers are fine, its only websites with CLI-token preference, whether its through manual downloading through any browser or said CLI routes.

I've narrowed down the problem a bit further, in that it seems if I limit my download speed under 20 MB/s, or even have multiple downloads going at the same time (making same effect since I peak at around ~25 MB/s just above the problem line), it is 90% more stable, just sometimes has a timeout in the 1st second when limiting, probably due to initial burst before limited can take effect. Also timeouts can happen anywhere from immediate, to 1 min if lucky.

There's really no solid errors i've been able to track down using netstat or netsh traces during a timeout, the connection just gets a generic timeout far as I can tell. Probably server dropping me on it's end due to something wrong on my end if I had to guess.

given the fact that the speed being limited holds the connection, I'm sure there must be an advanced setting or 2 out of place that's just not compatible with the download locations, being repo like sites, making the connection unstable, i've messed around a little with MTU with no luck, but maybe there is just a different value for my speeds/case/use or other likewise settings? i'd like some guidance on all, or at least various, applicable values/properties/settings/etc. that would apply to this situation if at all possible.

would help a lot as only 1/4 CLI apps im using have download recovery ability and the sizes are about 2gb a file so getting this fixed would be a huge help, also, it may be interfering with my windows updates as well.

Extra Info: ethernet wired connection, only PC in home,

internet is a fiber connection through a gateway router modem combo, ping, speedtest, and everything else about internet seems fine,

Windows 11 Pro insiders edition, 16GB ram, 12GB vram Nvidia, Ryzen 7 AMD

It would be nice to retain my full speed if at all possible, but if some universal cap of 20 MB/s ends up being the end case, its not the end of the world losing 5 MB/s, if that ends up being the solution, something in system and with a more solid clamp would be prefered to get 90% reliability up to 99-100% would be my goal in that case, as im currently using 3rd party software to do this which is not ideal.

any guidance on which settings I should be looking at would be appreciated.

Edit: oh one last important bit, all these repo sites, use port 443 UDP if that's relevant as well, already tried routers port forwarding and windows firewall with no luck.