I take advantage of this thread to include some of the recommendations that I compiled from the various popular media.
These reference data can be modified according to the requirements of each service, but they can serve as an indicative starting point.
One tool that can be useful to have updated data on the requirements of each service is this:
A priori, this online tool seems interesting to me because I suppose the developers will have updated data about LUFS value changes in the platforms they list.
I only use one audio track (playing my bass), and for me, the reference value is -16 LUFs (YouTube). However, in my videos, there are no narrations, only music.
I add the SC filter “normalize in two steps”, set to -16 LUFS and press the analyze button.