Yes, should work with [...]. Did you try? Is there any problem?
However, I strongly recommend to use host names. There is almost no reason for using IP address directly.
Will davx5 use the IPv6 of a given URL (if I enter an URL instead of the IPv6 address itself) if the DNS record contains an A record (IPv4) as well as an AAAA record (IPv6)?
DAVx⁵ uses okhttp, which tries alternative addresses if the first one doesn’t work. So if IPv4 + IPv6 are defined for a host name and one of the protocols doesn’t work, it should try the other.