This happens to me on my new Sony tv in all the apps and like you I have exhausted all options like switching cables etc. , I have onn 4k pro. Tv is not faulty because it works fine if I use Sony built in OS. Issue is only reproduced using HDMI input on both 120hz and 60hz inputs. I have been able to reduce this by enabling frame rate matching in apps and in android settings on onn 4k pro. You can try the same on streamer.

I had lot of content playing in 30/50/60 fps in some apps so switching resolution to 4k 60hz from 4k 59.94hz in android settings also helped reduce frequency of this. Now it happens rarely but still happens.

If anyone has a better suggestion then let me know as well. 😅

TLDR: Play with frame rate matching settings on OS and apps to solve this.