Big WI-FI speed differences Between Two Phones

[startac4]

I have a very significant difference in the wi-fi speed on my main phone (LG K20) and my travel/BKP phone (Samsung Galaxy J2) with Avast speed test. Testing the speed in the same location with same router, LG speeds are 55 down / 28 up; Galaxy speeds are 0.04 down / 7.6 up. Both running the same release of Avast. Ran Ookla speed test from Ookla website and get Galaxy speed 33 download but can't get upload speed to be displayed. Anyone know how to get that displayed? Should I download the Ookla app from Google play and use that? On my computer Ookla does display both speeds.

 

[Dannydet]

Possible factors could be :
Device capabilities
Interference
Distance
Obstruction
Network congestion
Wireless standard
Device sensitivity