~/.config/mpv/mpv.conf:
# Avoid creating a window larger than the screen
autofit-larger=80%x80%~/.config/mpv/input.conf:
# Copy timestamp
n run sh -c 'printf "%s" ${time-pos/full} | wl-copy'
# Reload subtitles
r sub-reloadWarning
Replace wl-copy with a system paste buffer tool if not using Linux Wayland environment.
For example, it would be pbcopy on macOS.