On Tuesday, July 28, 2020 at 6:38:45 PM UTC+1, wrote:
Ive been using MakeMKV, but I find the resulting files are between 4 and 5 GB.

Am I doing something wrong?

Probably not. MakeMKV 'only' does the decryption and extraction'; you are
getting the full content of the DVD/Blu-ray (including, potentially, all audio
tracks, director's commentary, etc, etc).

You might then choose to transcode to somethings smaller with a separate program

I tend to use (on Linux) MakeMKV for 'difficult' content extraction, and then
Handbrake for transcoding.