Same issue. Spent two hours chatting to Apple support. No idea or awareness of the issue, but very patient and attentive all the same. Still working with them on the issue so we’ll see what happens. Pretty darn sloppy though.
Lower res content seems OK. What I “experience” feels almost like a rendering bottleneck, or display delay. Almost like the processor or display mechanics can’t keep up with the data being received.
Applies to local and streaming media in TV app when using HD 4K content. HD on it’s own and “standard” def seems to be better, but it’s very subjective.
Netflix, again, “seemed” OK but my hut says it was not quite right. Amazon the same... HD stuff recorded on my 7plus just weeks ago was fine, regular, slo mo, and time lapse all OK.
Will try and update as and when I get any news.