A lot of stuff I watch is 720p, and it's okay with that. But with some types of higher quality files it can be (very) slow.

That said, I have replaced most of my "exact seeks" with "sub-seek"; in input.conf:

  Alt+Right        sub-seek  1   # Go to next/previous sub (within demuxer-readahead-secs)
  Alt+d            sub-seek  1
  Alt+Left         sub-seek -1
  Alt+a            sub-seek -1

And then in mpv.conf:

  demuxer-readahead-secs=120     # sub-seek only works within this cache
  demuxer-hysteresis-secs=60     # Fill cache only if lower than this; saves battery

This allows me to fairly quickly skip past stuff that's not too interesting, while still actually following the gist of what's going on.

I think it's also bound by default, but I'm not sure what that is from the top of my head. You'll definitely need to set that cache as it's only 2 seconds or so by default.