Telstra Smart modem 3
same nonsense but older from what i’ve seen.
Telstra Smart modem 4
Won’t work with TP-link or other 3rd part extenders, telstra guarantees it works with their own wifi extenders.
Possibly intentional incompatibility. They’re updating their firmware to block compatibility with 3rd part devices instead of adding compatbility.
In the smart modem 4 wifi settings ->
Disable "Band Steering"
Disable power saving (APSD)
Disable Fast Roaming / 802.11r