I have a question about mixing the Deco M5 and X95 (AX7800) models on the same mesh network.
Currently, I’m using Deco M5 units in the following setup:

I have a router from my ISP (fiber optic), which I disabled all network management options on (including Wi-Fi). This router is connected via an ethernet cable to my main Deco M5 unit, set to operate in Wi-Fi router mode. Unfortunately, both the ISP router and the main M5 unit are located in a closet, which isn’t an ideal placement in my house.

I have another M5 unit connected via ethernet to the main M5 unit, and it's positioned in a much better location in the middle of my house. However, I'm experiencing inadequate Wi-Fi signal in some areas. To improve this, I'm considering replacing the second M5 unit with an upgraded model: the Deco X95 (AX7800). I believe the X95 will provide a significantly better Wi-Fi signal.

According to the TP-Link website, all Deco models can be mixed, but I’m concerned about potential drawbacks of using an older model (M5) as the main unit. While I have the option to buy two X95 units and replace both the main and secondary units, this would be much more expensive. Therefore, I’m wondering if simply replacing the secondary unit with the X95 will be sufficient to improve the Wi-Fi signal throughout my house.