I tried a few video players (MPC/VLC/WMP) and all had similar issues so maybe hardware is the issue.Could be the video player you're using and whatever platform you're using it on. It's encoded with AV1 so if you have a weaker CPU or GPU from before ~2020 it may have troubles.
I'm running an R5 3600/2070s so kinda surprising porn videos are what is bottlenecking it.