Are there other methods for negotiating QUIC at the transport layer other than ALPN (Application Layer Protocol Negotiation)?

The method that I am referring to is for negotiating QUIC via ALPN by negotiating for an application layer protocol that requires it (like HTTP/3).

My issue with ALPN is that it is designed for choosing the application layer protocol, and not the transport layer protocol.

I see this as a limitation, because I think it should be possible to transport other TLS-based protocols over QUIC (not just HTTP/3), because QUIC implements DTLS. I believe you can transport them directly over QUIC, but I am not sure if there is a way to negotiate for it.

The reason why negotiating for QUIC would be important is consider a message being sent over a protocol like HTTPS or SMTPS. How could a client know to send the message over QUIC instead of TCP+TLS (other than specifying it directly)?

In short, are there other methods for negotiating QUIC (UDP+DTLS) at the transport layer? And if so, are the ways to negotiate back (to TCP+TLS)