After updating to new app, disney+hotstar is telecasting only in 1080p even if we select 4k in video settings for all the 4k content and no Dolby vision tooI have even kept on Auto and Premium HD buddy, it always played in 4k @ 25fps. I don't know what's the issue that he has faced, but it's not case with everyone.
It goes to 1080p when the network speed isn't sustainable for 4k, that should be case as well at least for me, instead of buffering every now and then.