Hi all, have read about the same problem concerning white&black sparklers on screen. Did alot of research prior to purchasing my Vizo 65PQ-F1, purchased from Sam's Club. Can't recall exactly were I read it at, but like was mentioned (Certified Premium Cables) r the first thing. Really cheap at Monoprice. 4K@60Hz, HDR, 18ghz Speed, 28AWG YUV 4.4.4.
Second this sounds like it also could be
Hdmi handshake, disconnect all cables from sources, do a soft reset on the TV, Avr, & Source. Then reconnect all, power up in this sequence. First TV wait 5 sec Avr wait 5 sec finally Source. This should correct problem, if no joy seek repair or replacement. I just love my PQ coming from a 6yrs old panny gt50 which I just loved. Paired with My Denon X6400H, I just let the 6400 do the up scaling problem solved, Ota is not too bad. My one only downside would be the viewing angles, I'm so used to the Panny Gt50 in that you can sit off angle an still no picture deter gatien. But I knew this getting this TV. The downside to Led/LCD unless you go with Oled or top the line Qled's. Hdr/Dolbyvision is bright an right on point. SDR content work's better when FALD is set to Low Picture Mode setting in Calibrate* & Calibrate Dark*. Otherwise you get Bang for your Buck.
So far, so good, going on my 4th week.
Also have SquareTrade + Sam's warranty