Sorry, that's down to my lack of familiarity and partly the reason for my questions. Is the reason a router is classed as a "mesh router" because it has a particular hardware capability or because its running a mesh capable OS such as OpenWrt?
To quote:
Convexa-S is equipped with Qualcomm Wi-Fi SON (Self-Organizing Network) mesh technology to deliver robust and consistent connectivity to your entire home.
On the other hand, if I can install OpenWrt on BT Hub 5s which can be had for less than a tenner, then why bother with more expensive routers? That was really the questions I had in mind. Its not clear to me from the description in any of the below links what makes it a "mesh router":
The Hub 5 also has ac1300 WiFi so superficially at least, the hardware seems to have a similar capability except that the Hub 5 has less memory. I had also seen a thread on here where someone got a mesh of Hub 5's working so its evidently possible.
"AX capable" is a new term that I have not come across yet. I can see from a bit of Googling that WiFi6 and 802.11ax appear to be synonymous and that ax supercedes ac, so ax appears to the the next generation of WiFi. I am therefore guessing that "AX capable" means it is capable being upgraded with AX supporting firmeware? Those GL iNet devices appear to be ac devices as are ones you mention above, but its clear that the above are definitely tri-band (2.4GHz + 2 x 5GHz).
I guess I can also aske the question, is having two or three radios synonymous with dual-band or tri-band? I had always related the latter to actual frequency ranges supported rather than the number of hardware radios implemented.