Yes. Last I checked handbrake used FFmpeg in the background.

It does indeed!

It does use some parts of libavformat, libavfilters, libavcodec. But HandBrake it's not an FFmpeg cli UI and it's quite different.

handbrake is such an underrated tool! I've been using it for over a decade to compress and convert videos, and nothing comes close (except ffmpeg ofcourse)

Or Permute on MAS/Setapp

I've not found anything better than StaxRip if you want access to the deep guts of encoder options. It can use nVidia's nvEnc API either directly, or through ffmpeg; same for Intel's QuickSync and AMD's VCEEnc.

https://staxrip.readthedocs.io/generated/screenshots.html