easy to try solution for slow ethernet upload speeds

Easy to try keyboard solution if your ethernet connection download speeds remain unaffected but either occasionally or continuously, internet upload speeds using ethernet are in the low kB range making the connection unusable.  Pertains to Windows 10 and 11 installations.

Go to device manager - network adapters - select your ethernet adapter (may be called ethernet controller) - properties - advanced properties tab - Jumbo Frame - change the Value to 9KB MTU - hit the OK button

That's it!  Hope it works for you.  Worked for me on two different model desktops, one running Win10 and the other running Win11.  I don't know if it is a true fix or a work-around, but at least for me it solved the problem.