Recently bought the qn90f samsung tv and I'm also facing the same issue, checked some youtube video and googled the solution, they asked to reset the smart hub as the last option, I tried that as well as no other option like clear cache, clear data, ...
In samsung members app, when you will go to Discover tab > Beta Program card > three dots on right top corner, you will find beta program settings, from there you can choose withdraw from beta program.
One UI 7 has some major battery drain issues, you're lucky you haven't got it brother.. enjoy what you have and directly upgrade to one ui 8 even if you get one ui 7.
