Thank you very much for the suggestions!Dolby's recommendation for music is Music Light (just a touch of DRC)
I've never done anything with movies so best to do Google it or (Chat GPT), but but gut says 'Film Standard'
I would recommend 16 for TrueHD Channel Presentation for decodes
BTW: If you are doing encodes, I would also encode to 5.1.4 minimum. Even though you only have 2 on the ceiling now you may expand some day and an AVR with Atmos decoder will route .4 to your .2 nicely.
What I got from ChatGPT is that the recommended DRC profile is (obviously) environment specific.
Meaning that for environments like a home (theater) room with low ambient noise Film Light can be used, while in more noisier living rooms, Film Standard can be a good choice. Film Standard is also more closer to the DRC profiles used in the Cinemas (bigger room size and higher ambient noise)
In most cases, Dolby Atmos tracks on 4K Blu-ray discs are/should be mastered without significant dynamic range compression. Ultimately it depends on our personal preferences and the specific characteristics of the listening environment.
I have also found an older article with some DRC profiles related infos.
https://www.soundonsound.com/techniques/surround-sound-explained-part-5