My 4b Pi(s) are 8 gb with 32 GB Micro SD cards - the videos are on a 4TB WD USB 3.0 Drive.
Desktop is MATE (Most like Windows XP interface).
Running Leap 15.4 with packman VLC and codecs,
Running 720P there are almost no dropped frames. (6 frames in 30 minutes of video per VLC Codec info)
If I switch video modes to 1920P
Running 1920P about every 4th frame is dropped so video is jerky - sound is fine. (134 frames dropped in 466 frames played)
This does it VLC or Firefox playing Youtube videos.
I really want to retire some old Levono Ideastick 300 attached to TV to play videos.
Tumbleweed 32 bit was unsteady on the Ideastick 300 but Sparky Linux 32 bit works fine. Just not crazy about Debian based Linux.