Hi,
What is your goal for this question: are you looking to apply for a DBA position, hire for one, ... ?
Assuming you are referring to
tiered support levels for DBAs, you are probably best asking or researching this question for organisations that are similar to yours (or that you might be interested in joining). There is no specific standard for MongoDB DBA roles, so companies will have different team structures and expectations. Tiered DBA levels may also imply a certain level of experience ( junior / intermediate / senior ).
I also wouldn't assume that all organisations have tiered DBAs or support roles. There are alternative models such as collaborative support.
Regards,
Stephen