I am trying to show client count on different AP-s, under the AP appearance (client count OID) in DUDE, but the client count is 0.
The AP-s are managed by CAPSMAN, so the registration table on the AP is empty.
You need to use the Oid of the Capsman Registration Table
oid("iso.org.dod.internet.private.enterprises.mikrotik.mikrotikExperimentalModule.mtXRouterOs.mtxrWireless.mtxrWlCMTable.mtxrWlCMEntry.mtxrWlCMAuthClientCount.[interface number]
You can look through the snmpwalk in dude on capsman device
PS You could do something like this