ac1750 b1

I have one of these devices and its constantly disconnecting from the network, sometimes it's totally unresponsive and I have to reboot it (like just now). Supposedly this is a supported device, but I'm wondering now. I have no problem supplying logs, but I'm not sure if the current logs would...

I'm currently using RT-AC88U and want to use AIMesh system so I look in the market for the cheaper way to make it work and come across these 2 models which are RT-AC1750 B1 for $73 (not sure if this is RT-AC66U B1 upgrade? what differences in performance? Does it compatible with Merlin...