With your question I understand that you already have all the required certificate and key files to use TLS authentication.
Below is a sample rsyslogd configuration to use TLS from Configure secure remote logging with rsyslog (TLS) on Linux
# make gtls driver the default
# certificate files
$ModLoad imtcp # TCP listener
$InputTCPServerStreamDriverMode 1 # run driver in TLS-only mode
$InputTCPServerRun 6514 # start up listener at port 10514
Here you can replace the certificate and key file locations based on your environment, if you are using a different port then change the same for
The article uses GTLS as the default StreamDriver so you may have to install it manually if not already available
Also check SELinux and Firewall between the server and client to make sure they are not blocking the log transfer.