I wish I would have known this before purchasing the Foxwell 510elite.
It is a great scanner for most Merc models but any that use the 28 pin conn.
like my W210 it cannot access any systems period. They sell a 28 pin adapter
but it does not work with 510elite as you need the type of duplex adapter coming from the scanner like the 530 (same software) as 510elite and around same price. The foxwell scanners have 2 way communication that makes it

more like the very expensive scanners and in my opinion better than others like icarsoft. (I also have MBII icarsoft and the 28pin adapter but it lacks 2 way communication of Foxwell).
So overall Foxwell 530 or 520 with 28 pin adapter should do the trick for all of your Mercedes....
On a side note i just purchased the GM software for my 510elite for $80 bucks, and it covers thousands of GM's including 2021 models.
Hope this helps I know how you feel I spent lots of hours doing research and still should have gotten a different Foxwell model.