Synchronizing repository metadata:

https://documentation.suse.com/sles/15-SP3/html/SLES-all/cha-rmt-mirroring.html#sec-rmt-mirroring-synchronization

The main "complain" is that it is not written one should enable rmt timers... I do not remember how I installed RMT but I see "presents" are "disabled" by default:

---%>---
 # systemctl list-unit-files  |grep rmt
rmt-server-migration.service                                                         disabled        disabled
rmt-server-mirror.service                                                            disabled        disabled
rmt-server-sync.service                                                              disabled        disabled
rmt-server-systems-scc-sync.service                                                  disabled        disabled
rmt-server.service                                                                   enabled         disabled
rmt-server.target                                                                    disabled        disabled
rmt-server-mirror.timer                                                              disabled        disabled
rmt-server-sync.timer                                                                disabled        disabled
rmt-server-systems-scc-sync.timer                                                    disabled        disabled
---%<---

Thus, RMT server runs (rmt-server.service unit) but I was quite surprised not having updates (mirrored updates).

There is `systemctl status rmt-server-sync.timer' command, but it does NOT explicitly say to "enable"/start it.

Thus please do:

- add an explicit commands to enable/start needed units:

systemctl enable --now <unit>

- check wording of this part:

"... is done with the systemd timer rmt-server-sync.timer."

To be technially precise, I assume it wanted to say: The synchronization is timer-based activated by systemd <unit name> timer unit. That is, probably "is done" -> "is timer-based __activated__", so one understands clearly it is activated/triggered regularly by .timer unit.