P2TR MultiSig has been supported by Bitcoin Core ever since it supported TapRoot descriptors,
But just like its Legacy/SegWit P2SH MultiSig, it requires technical knowledge about "BIP341" and "Descriptors".

It added another layer of complexity compared with the non-P2TR MultiSig so I'm not surprised if it's rarely utilized by the majority of Bitcoin Core users.

This (BIP341): https://github.com/bitcoin/bitcoin/blob/master/doc/descriptors.md#examples
And this (descriptors): https://github.com/bitcoin/bips/blob/master/bip-0341.mediawiki#constructing-and-spending-taproot-outputs