I found one way, and you'll need the following software,
BadgerIT VOB2MPG (with custom installation instructions for Windows 10)
IfoEdit (v0.971 Public, see checksums) - For "Advanced" guide only.
Depending on what you have/want, you may need one of the following sets of instructions,
Basic - Convert the full DVD to .MPEG
With this method, you'll ...
ffmpeg has an amazing article on burning the subs into the videos.
I trust ffmpeg to be very careful with (the lack of) quality loss.
Given you are dealing with ASS, here are the important bits,
You can burn text subtitles (hardsubs) with one of two filters: subtitles or ass.
Same as the subtitles filter, except that it doesn’t require libavcodec ...