Questions about MikroTik hAP ax³

Yes, in any case, you simply operate it as a normal access point in a LAN, then all clients in the LAN and WLAN can communicate with each other. I also operate it this way. However, the platform is not a typical plug-and-play product. It is about as flexible as professional Cisco hardware, but has a fairly steep learning curve depending on the use case. For your use case, you're sure to find a YouTube video on how to configure it if it doesn't work out-of-the-box. If you don't feel like tinkering, another product might be better.