Upload speed slow on my windows devices.

[Dinomannen]

I have a 50/50 internet conenction. The download speed works as expected,50mbps on both windows and android (don't have access to linux or apple products), but my upload speed is not working properly on my pc's with windows, they all have windows10 home edition if that is relevant.
I am using speedtest.net and googles speedtester to test mye speeds. On speedtest.net i get between 3 and 15 mbps upload speed on my pc's, 15 for those in norway (where i am sitting) and between 3 and 5 on those outside of norway. Googles speedtest gives a consistent 5mbps upload speed. When i use the android devices to test to the same servers i get a consistent 50mbps upload speed. The pc's have been tested using CAT6 cable and wifi.
I also disconnected one of the pc's from the net and connected my phone to it with usb cable and turned on internet sharing via usb where the phone got the internet from wifi, in this setup the phone got 50mbps upload while the pc still got the same results as stated earlier. I have tested with 3 android devices (2 phones 1 tablet) and 3 pc's (2 laptops 1 desktop) and the desktop i even tried to reset the pc with the windows 10 reset function, no difference.
The consistency in the results beeing, windows low upload android full upload regardless of wifi or cable, which ethernet port on my pc's i use and even when using phone to share the internet has led me to believe it is something with windows.
I have searched around and tried all the possible fixes i could find, i have tested various versions of drivers for wifi and ethernet cards, including the newest one. And nothing has helped EXCEPT on my desktop before resetting windows i got an windows update, that i installed, after that installation i got the full 50mbps uplaod speed on it, for approximetly 4 hours, then it suddenly was unable to connect to the internet at all, but windows kept saying everything was fine and that it was connected, so i restarted my computer and it was back down to the 3-15 speeds. after that i have not seen any improvement in uploadspeed from the windows devices again.

I will list all the things i have tried and can remember.
Updating drivers.
Windows update.
Changing DNS.
Using VPN.
Turned off/on delivery optimization.
Turned off/on "Receive Window Auto-Tuning Level feature".
Turned off/on Large Send Offload
Adjusting Windows Reservable Bandwith Setting
Disabling firewall
Removing OneNote (it was on a list of possible fixes at one place and i don't use it so i tried.)

Thats all that i can remember right now.
Hoping someone here can help, and if there is some more information needed i will happily provide as much as i can.
Thank you.