Shotcut defaults (Stock preset)
H264 Main profile.
30fps
“Smooth playback is device dependent”
Here’s one of my files exported at a stock setting. (Originally 50fps [PAL country] )
It plays fine on all three of my PCs (ranges from 8, 10 and 12 years old) and TV.
If it stutters on some of your devices, then they don’t have what is needed to playback HD video.