Question about ASUS TUF AX3000 V2

Any WiFi-based mesh will result in at least 2x loss on each leg. This is because the same channel is used to both communicate between 2 nodes and the node and the device. The only way to avoid that is to use cable extension (which Asus AiMesh supports) or have a low-speed internet provider that is slower that 1/2 of the physical speed between nodes.
I have AX3000 v2 as the main router + 2 Asus AiMesh nodes on WiFi 6. While router gets nearly 2.5Gbps of internet, the smartphone in 3 meters gets only 300-400Mbps over WiFi and the same smartphone in 3 meters of a AiMesh node only gets 150-200Mbps.
In general I'd still recommend Asus AiMesh as it can be centrally configured. But try to get as homogenous setup as possible to avoid problems (e.g. all nodes support WiFi6, etc.).