Is it possible to create DANE TLSA records when the DNS server doesn't support it?

I'd like to set up DANE for the domain which handles my email. My domain is registered at OVH, and I'm using their anycast DNS servers. They do support DNSSEC, but not TLSA records.

Is there a fallback record type I can use? (like I can use TXT if the server doesn't support SPF etc)

I've been able to do it on OVH by generating a "generic" record (with TYPE52 instead of TLSA). This can easily be done using hash-slinger:

$ tlsa --usage 1 --selector 1 --mtype 1 --output generic --certificate /path/to/certificate.pem example.com
_443._tcp.example.com. IN TYPE52 \# 35 0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef012345

Adding this record in the OVH manager works just fine.

No.

The use of TXT for this in the case of SPF was done to allow for broader implementation, but it is not a general scheme, and there are disadvantages to that approach which preclude its standardization (mostly increased application complexity but there are other reasons).

If you need support for unusual RRtypes (which at the moment TLSA is), the best thing to do is to host your own authoritative nameservers.