Yes, the AX3000 Xiaomi Mesh Router can be used for mesh expansion with the Xiaomi
5G CPE Pro router.

Hi !
5G CPE PRO router from Xiaomi is not a MESH router

However, it can be used as an Internet source and must be connected to the XIAOMI AX3000 with an RJ45 cable

The first XIAOMI AX3000 (the one connected with the cable) then serves as a gateway for the MESH network with other AX3000 (wireless)

This gateway must not be placed anywhere else in the house or flat

The other AX 3000s can be placed in the rooms as desired and according to reception quality

The various AX3000s independently establish the best connections with each other

Greetings
Christian