Same issue with the out of sync. I have switched form My Roku LT (was purchased because it was told to me from support that it could be the problem) to my Play station 4 while watching the same show on Tubi and on HBO MAX and no sync issues on the Play station 4 and I moved the Roku from the Samsung TV in the basement to the LG TV in the master bedroom and still the same results. We just purchased a new Samsung series 7 (70) and after getting the TV set up I performed the same tests again and still the same issues on the Roku but no sync issues on the Play station 4. I tried the possible solutions as posted in the help forums (turning off sound and setting the Audio to Stereo and HDMI to PCM) and no change.
This is the 2nd Roku that I have purchased and also testing with 4 TVs and my test TV used for work with no solution.