I still believe it is possible.

This post:

https://bitcointalk.org/index.php?topic=5462088.msg62647223#msg62647223

Says we could only use PSBT's what is not true, signrawtransactionwithwallet works well.

I believe we can't use signrawtransactionwithkey to sign complex taproot script as the post says, but signing with privatekey path is not complex taproot script, so, maybe it is possible if we create the full command with the respective witness value.