I take a look to
your message error and it s looking very similar to this
old stackoverflow thread.
In that thread they say that the prob of location that used buildozer to download Android NDK have been fixed.
What version of Buildozer did you use?
Check also that your firewall or antivirus is not blocking your ubuntu installed on your WSL2 to download files. It has happened to other users.
If you have the correct version of Buildozer and your firewall is ont blocking downloads in WSL2 perhaps you can try the fix that was proposed in the old stackoverflow thread :
"The solution is to manually download the ndk from the working URL, unpack it and place the unpacked folder as new subfolder into:
/home/<your-user>/.buildozer/android/platform/"
But i m not a specialist of buildozer (yet :)) and @Robert perhaps know something better.