These streaming settings are determined by DRM & HDR screen certifications. You can compare stats from DRM info app for both phones. Generally Widevine L1 certification is recommended for best streaming. In iphones the data consumption limit even higher like approx 5 GB/hr at best settingRecently my cousin bought a new phone, Vivo Y51A. I checked the streaming quality on Prime Video. There is a change in size while streaming. Have a look.
But on my OnePlus 7, it's still the old settings. Why?
My app is on the latest version. Signed up for Beta version, thought it may help.