Nothing should share the same IP address. They share the same subnet as setup by your router. I have a NETGEAR R6700. It has two subnets. One is private and one public. The two subnets are segmented from each other to allow you to give a visitor access to the internet (public subnet) without being on the same private subnet as all your personal/family gear.
Both networks have an associated WIFI SSID. They are separate and have their own passwords. The Wired portion of the network is only on the private subnet. The reason is you don't give people wired access to your router unless you fully trust them. I trust my friends but they don't need access to my home computers. This is a security feature.
The warning from the Brennan network setup page says: The dongle supplied with the B2 is for the 2.4GHz WiFi band only. It recommends if you have a shared setup like I do with the same name (SSID) for both to turn off the 5G while you configure the B2. The AX uses both 2.4G and 5G to achieve its speed.
So you should be able to connect wireless and wired to the same subnet. The same subnet typically means the first three numbers of the IP address are the same. Mine are 192.168.1.X. The X is unique for each device wired or wireless. This is completely controlled by the router. All setups must be done there.
I use my phone (android) and iPad as a wireless connection to my private home network. My B2 is connected by wire as well as my home computers. Video games and TV are on the wireless. They all talk to each other seamlessly.
I would expect your router is capable of similar setups. The wired connection is less of a load on the CPU in your B2 with a larger bandwidth to the network. It works significantly better for me. It is three feet from my router so WiFi signal strength is not an issue in the comparison.
So on a whim I did a search for AX-WIFI, I thought it was a brand name. Turns out you may be referring to 802.11AX, the next generation WIFI after WIFI 5G. The B2 only connects with 2.4G so I assume your router is downward compatible and connects with 2.4G. It will not communicate at AX speeds.