Holy crap. I’m patting myself on the back. Finally deduced a problem with a solution that doesn’t seem to be mentioned anywhere.
I read through the long post on stackoverflow, to see if there was any other insight. The author mentions another method of adding
[boot]
command="sysctl -w vm.max_map_count=262144"
to the wsl.conf file in your WSL host, then reboot. This caused Docker Desktop to completely fail. I had to remove the edit to get DD working again. He also went on a tangent about systemd and how to enable it. Lo And Behold it apparently was enabled by default. So, I tried your command:
echo "net.core.rmem_max = 2500000" | sudo tee /etc/sysctl.d/nextcloud-aio-buffer-increase.conf
which did nothing. It was ignored, just like editing wsl.conf and .wslconfig. I deleted the file that was created, then I then realized I could add a line directly to /etc/sysctl.conf; since he says the ‘normal’ methods would now work. At the bottom of the file I added:
net.core.rmem_max = 2500000
which finally cleared the error…Whew! 