Get online support
When NBN first came to Penrith NSW I got FTTP and I still have the original modem they supplied me
NetCommWireless N300 NF12. My plan is Ultrafast Unlimited.
I brought a SwannBuddy Video Doorbell.
I had to buy a new mobile phone, Oppo Reno 10 (other phone was to old)
When I started the Wi-Fi was 100% strong I fixed it to the door frame
The Wi-Fi went down to 20%
What can I do buy a new modem?
Buy a booster?
Or go back to the old bell.
You can purchase a third party modem/router that will support all of your new devices.
Then use the old one as your access point, that will help boost your Home WiFi network.