What were you trying to do that didn't work?

This is somehow a continuation of RHEL-144930.
postgresql.conf has a ssl_ciphers property to configure ciphers, but it internally ends up calling OpenSSL's SSL_CTX_set_cipher_list() function which is for TLS1.2 and lower only, not TLS1.3.
TLS1.3 ciphers are configured through callin OpenSSL's SSL_CTX_set_ciphersuites() instead.
Due to this, it's impossible to configure TLS1.3 ciphers for the service, it's only possible to do so through using ssl_ciphers = 'PROFILE=SYSTEM' but this then uses the system-wide policy, which is not always suitable..

What is the impact of this issue to you?

Can't restrict TLS1.3 ciphers without affecting the system-wide policy.

Please provide the package NVR for which the bug is seen:

postgresql-server-13.23-1.el9_7
and all the streams.

How reproducible is this bug?

N/A