I turned on the SUV today and “active parking assist and parktronic inoperative” showed up on the dashboard. I tried to turn on and off the car a few times but nothing helped. The parking sensors and cameras are all off. I had to park the car without getting any sensor or camera data.

That's normal for an MB EV. It'll probably be fine tomorrow morning. They even put a little blurb about it under "break in" procedure in your owners manual.

I came from Audi Etron and for the past year, it has zero electronic issues. Makes me think twice about being a long term EQS owner.

That’s the least of issues

phantom stopping
doors don’t open
hatch doesn’t close on 1st push
screen for nav blanks out

not to mention 40% resale after 1 year

If you haven't already, it might be worth checking to see if all cameras and sensors are free from dirt.

After a few hours sitting in the parking lot, the problem went away.

Same thing here on my W206. Two times already this year. It went away after I turned off the car for ~10 minutes and turned it back on. In the meantime I cleaned the sensors, just in case.

I think its just necessary to reset the car. But the reset will not happen immediately after you turn off the car. That will only turn off the engine. You need to wait a while (sometimes up to 20 mins) until all car systems shut down.