I think my CPAP (AirCurve 10 VAuto) draws 250w. It’s all I used and it went from 100% to 40% in the first night.

Jackery Explorer 1000 Portable... https://www.amazon.com/dp/B083KBKJ8Q?ref=ppx_pop_mob_ap_share

Agreed. IMHO, Hondas are the most reliable and hold their value well, and have a lot of service shops for them. You would still have to put it outside and run an extension cord or something.

https://smile.amazon.com/Honda-EU2200iTAG-2200-Watt-Generator-CO-Minder/dp/B08GPKL8N2

I can’t see the specs for the machines, but if you need 500 watts total and you just need to run it for an hour or so in an emergency, you could do something like this, which you could use inside the apartment. But the Honda will run for days and days, this is more of an hour or maybe two type of thing:

https://smile.amazon.com/Jackery-Portable-Explorer-Generator-Emergency/dp/B083KBKJ8Q

As with all backup generators and other power solutions, you need to plan to practice with it, test it regularly, change the oil, keep stabilizer in the fuel, etc.