@rsingel Hi, welcome to the community. Are you able to constantly reproduce this issue? (like turning on QOS and setting it to 1024mbps download/upload, the speed from satellite Deco XE200 instantly...

@DerekColley Hi, Thank you very much for the feedback. Deco P9 with the latest firmware 1.2.1 doesn't support the "Static Route" yet. Best regards.

@browri Hi, Thank you very much for the feedback. It is suggested to install the latest beta firmware here for Deco BE85_V2: https://community.tp-link.com/en/home/forum/topic/697580 Best regards.

@DalTxJim Hi, Thank you very much for the feedback. I'm afraid that the Guest Network doesn't support settings "Connection Preference". Best regards.

@HIDavid It is also suggested to remove BE63 from the APP(or reset the satellite BE63 by holding the reset pinhole for 1s), then click "Replace Main Deco", such as How to replace the main Deco with...

@Derwood9937 Hi, Thanks for the feedback. Did you use any network switch to establish Ethernet Backhaul? ---If possible, can you connect one of the satellite Deco XE75 pro directly to the main Deco...