Sorry, no video for the range test. I don't have a YT account and never publish any videos. I record videos only to find the drone in case I lose WIFIThat's interesting about the Xiaomi nano Youth router. Would be cool if you could post a video of a range test with it and the Tello.
Can you tell us which phone you use?
I've done a bunch of research and I believe the phone matters more than a wifi extender.
If you notice, Ryze only has a small list of compatible phones - Ryze Tech
If you don't have one of those EXACT phones, the Tello will work but the video will have artifacts and dropped frames no matter what else you do.
I only use my drones for flying FPV and sometimes for making photos.
I use a Samsung Galaxy S6, but a quick test flight doesn't show major issues using my old S4.
Of course you need to have good close range video when directly connected to the drone to start with, otherwise even the best extender doesn't help.