@Sledger17 Yes, the US version should be compatible with band 4.

@Luca21 You can find it here as per the router version: https://community.tp-link.com/en/home/forum/topic/241534

@Jks Is the model number of the TP-Link router Archer C1200? Is it V2 or V3? You may find this on the router bottom sticker. Is it working as a normal router or access point? Please refer to this...

@SebastianJ Actually, what I meant was what if you remove the extender from the Onemesh network and make it work just as a normal range extender, will the issue persist? When the devices connected to...

@M_A6USV2.1 It is suggested to upgrade to the latest official firmware if you are experiencing an issue with the current firmware, we will work it out if the issue persists.

@Onknight How many devices are connected to the AX20, wired and wirelessly? What is the bandwidth you paid for the internet? Try to optimize your wireless network, for the devices with small traffic,...