I use what is local and available that has on the side:
"MB229.3 Approval" or "MB229.3 Approved".

I only run 5W40, I have used 5W50 but that was when I was pushing the Graphite car HARD in 90F weather.
MB no longer recommends 0W40, it is still approved, and if I lived where I did a lot of cold starts below 40F, I might use it.

Here is the worldwide list, most are Euro oils but you can find a lot of them locally. Notice the emphasis on 5W40.
https://operatingfluids.mercedes-benz.com/sheet/229.3

As to the AUtomatic, as one transmission shop owner told me, "If you change fluid and filter every 50,000 miles, you would put my transmission shop out of business". If you expect the car to die by 200,000 miles, then don't service the fluid in the transmission after the first service (which should be well before 80,000 miles). ALL fluids take on moisture and contamination. Given the age of the car and the fact that most owners never service autos OR manuals, I'd NEVER buy an automatic with more than about 50,000 miles on it. In fact, I NEVER have. Take note: I've driven autos maybe a total of 100,000 miles. I've NEVER had a transmission issue, not once.

I go so far as to change my differential and manual fluid every 50,000 miles / 5-6 years.