@hornet55 Please provide a screenshot of the status page of RE200 as below. And also sent me the system log file of RE200(Go to "Settings--> System Tools-System log"). Then I can provide further help.

@PJHudson87 You can get 100Mbps from your router wifi, right? This is got when your device is connected to router's 2.4G wifi? Please double check this. Normally, 5G wifi has better speed than 2.4G...

@Dlc You can get 220Mbps from your router wifi, right? This is got when your device is connected to router's 5G wifi. Normally, 5G wifi has better speed than 2.4G wifi, but 850RE only supports 2.4G...

@Langa Please check this Guide: Adding an additional unit to your TP-Link Deco network

@Chlo There is no utility for range extender. You can just login to 850RE web mangement page to set Power Schedule. 1. Connect your device to extender wifi. 2. Login to extender with...

@PG17 Please follow this to reconfigure RE205: Range Extender Setup video