Got the AX23  router 6 months ago, and  2 mesh extenders (RE 215). worked really well for first 4 months or so, then started to constantly drop internet connection.  No speed or coverage issues. Small house and we can get our advertised speed (150 mbs) when its working. 

Internet signal is fine, if we plug the modem straight into a pc or the google streamer with wired connection no issues. Full speed, no interruption. Modem always shows full connection.

We have 3 LAN devices from the router normally and 6 wifi devices.  Often some devices will lose internet but not all. Wifi vs wired doesnt seem to matter. 

Did a factory restore of router a month ago, but within a week or so went back to dropping internet. Powering down / rebooting router fixes for a while (anywhere from 5 minutes to 24 hours) 

Firmware was updated to latest version yesterday but that has made it worse if anything. 

When  acting up the router is not discoverable in the Tether App / local login. The Tether app will show a generic "TP LINK ROUTER" or no router at all - it will just show the two extenders.  

Not a techie and at my wits end with constantly rebooting the router.