Not exactly familiar with this 2.6 engine.  But considering MB pretty
much keeps the same design principle across all its models (at least
around the similar years), the procedure may be similar to the 190D 2.2
engine which I have done.

If so, you need to raise the engine as much as possible, probably 3-4".,
without disconnecting the drive shaft.  The rear end of valve cover may
touch the firewall and that's the max you can go.  The oil pan can then
slide out.  Both the cross member and oil pump are on the way so it is
not easy but you should be able to figure out how to slide it.

The oil pan construction is solid enough to support the engine weight,
at least temporarily, so if you don't have engine crane you can still
jack it up.  But be VERY sure to support the pan evenly, ideally with
broad wooden block, or you run the risk to crack it.

2.6 engine is quite large for W201 engine bay.  I am not sure if there
is enough clearence in the front, between fan and radiator, since the
engine will be tilted a little bit.  If not, the radiator may need to
come out.