Generally the price premium for XLRs over unbalanced cables is pretty small. Transparent are an outlier because the bulk of the cost of a Transparent cable is the networks. This is evident from the fact that Transparent charges relatively little for additional lengths of cable. But balanced Transparent cables need a network for both the hot and cold signals, hence the premium.
One small aspect of XLR's that I prefer is the fact that the pins and sockets in an XLR plug are identical, whereas in an RCA you have a circular negative connection that then has to transition to a different form factor to allow a wire to be soldered to it.
@OP Shunyata Thetas are worth adding to your audition list.