Yes, this is all normal:
positor1 I have two asus ZenWiFi AX and only ever see one SSID for the 2.4 and one 5ghz band that i have separated.
MarkyG82 I'm pretty sure the standard mesh setup is for one visible SSID
Every wifi Access Point device (whether you call it a router, repeater, or mesh) has a unique MAC address. In fact so does your phone, laptop, etc, not that that's relevant.
So if you have say 3x Access Points (be them Mesh or otherwise) set to the same network name ("SSID"), then all wifi device hardware on that network will see 3x separate devices with different MAC addresses. Or more accurately, they'll see all the ones which are in-range.
But, depending on the device you're using, these 3x Access Points are presented differently:
Most clients - e.g. your phone - just summarise it by saying "hey, I can see at least 1 Access Point on this SSID, and the strongest AP has signal strength nn%" Even if they can see other AP MAC addresses with the same SSID, they don't bother telling you that, because it doesn't really matter.
Other clients - e.g. the Giv dongle - list every individual AP and all their MAC addresses. In fact the admin screen for most Mesh wifi will show you the same SSID repeated many times. Once for each AP.
Also, don't forget that for many years before Mesh we had large-scale corporate wifi (e.g. hotels) with the same SSID across many APs. As your laptop moved around the building, it would always just connect to whichever AP had that same SSID and the best signal. You'd connect to wifi in the lobby, and it would still work seamlessly an a different AP near your room.
Edit:
What I don't know is whether the Giv dongle is specifically binding to a particular AP's MAC address, rather than the normal behaviour of just roaming to whichever one has the strongest signal at any given moment. If it is binding to one MAC, then it's important that you select the right AP for it to connect to...
I can check this behaviour for you - if I go disable the nearest Mesh AP to my Inverter, I can check and see if it roams to another Mesh AP seamlessly or not. I'll check shortly.