Inverter upgrade and subpanel addition

[Brummi]

I would like to upgrade the MSW inverter in our 2017 View 24J. to a 2k pure sine wave inverter. As part of that, I want to power additional outlets with it (currently only the TV above the sink and the dinette outlet are powered by the inverter)
I'm thinking about the Xantrex Freedom Pro inverter, but I would like to ask the community for recommendations. I am also looking for advice on how and what kind of subpanel to use. There is not a heck of a lot of room left under the bed......
Secondly, does anyone have any experience with a ResMed CPAP? I bought a 12 volt adapter, but now I have doubt whether I should add a 12 volt plug in the bedroom or just use it on 110 volt with the inverter running. Is it more efficient one way or the other?
Thanks in advance for any input.