Hello TP-Link Community

Since I've changed my network equipment from ASUS to TP-Link DecoXE75 I've had issues with buffering on both my LG Smart TV's when watching Disney+, Netflix and other streaming services directly on the Smart TV even when the TV is the only device using our broadband.
First of all, I've never had this issue before with my old router.

I currently have 2 DecoXE75.
The first Deco is my main and is being used as our main router and is connected to our modem from my ISP in bridge mode.
The second Deco is connected as a mesh wirelessly.

Most of my devices is connected to my 2,4/5Ghz network, except all my smart home equiptment that is connected to my IoT network and my gaming PC and mobile that is connected to my 6Ghz network.

My internet speed is 500Mbit/s Download and 500Mbit/s Upload

I've tried following things to try and fix it myself:
- Added both Smart TV's as "High Priority"
- Made sure that the TV's are connecting to the closest Deco (The TV in the livingroom is connected to the main Deco and the one in my bedroom is connected to the second Deco)
- Tried restarting the Deco's (Even tho I've made them restart every monday night)
- Tried connecting them to a newly created IoT network running 2,4Ghz, just to see if that made a difference

I don't know what I can do about this, so I was hoping some of you could help?
It's a bit frustrating, due to it not being an issue with my old equipment. 

Thanks
C. Steinhaugen