I cannot connect my microsoft account to my playstation

Like I said originally, I'm aware that once you link a microsoft account it is permanently linked to that playstation account. There has never been a microsoft account connected to my playstation account. There has actually never been a microsoft account connected at all to the playstation I'm using.

Sony will only allow you to connect a Microsoft card to a single PlayStation ID. This cannot be undone, and the ID cannot be connected to another account. So you need to use your PS4 account

Unfortunately, Sony does not allow you to change the connected accounts. Once a Microsoft account and a Playstation account have been linked, that's it. You can unlink them but you can never link that Playstation account to another Microsoft account and that Microsoft account cannot be linked to a different Playstation account. This is all Sony's decision. The linking is handled on their end so there is nothing that Microsoft can do about it.

Playstation does not allow you to connect different accounts to the PS account. Once a PS account and an Xbox account have been connected, they cannot be connected to any other account. You have to use the original Microsoft account.

Microsoft cannot help you. Your Microsoft account is linked to Playstation on Playstation's servers, not Microsoft. I have seen dozens of cases like yours and while Sony support sends people to Microsoft support, Microsoft support cannot do anything since the account linking happens on Playstation servers.