According to docs: https://learn.microsoft.com/en-us/powershell/module/defender/set-mppreference?view=windowsserver2022-ps

1 Set-mppreference works for -ProxyBypass -ProxyPacUrl -ProxyServer -SharedSignaturesPath -SignatureAuGracePeriod -SignatureBlobFileSharesSources -SignatureDefinitionUpdateFileSharesSources

however after setting a value you cannot remove them back to default *none.

example:

set-mppreference -ProxyBypass 0 #works

then,

remove-mppreference -ProxyBypass 0 #doesn't work

Please test a way to make one of the "proxy" and a way to make one of "the others" work, since they give two different errors.

2. Set-mppreference -DisableFtpParsing 0

and

Set-PSComputerName MyPC

Doesn't exist for some reason, some people call these two "unsettable Defender properties" and they don't exist in the docs, why?

Also asked on https://answers.microsoft.com/en-us/protect/forum/all/mppreference-questions-how-to-remove-defender/45c1c877-e0eb-443d-a553-231bb1b77a46