Reading between the lines, it seems that elements of what used to be the operations group hasgroups and launch groups have become the Delta, with Mission Support and Medical Group becoming the Garrison. There was another group that reported directly to the Wing Commander, for decision support and financial assistance, which may have been consolidated further.
And finally:
twice "the Space Launch Delta 30" appears, and the "the" puzzles me.
Mostly likely a leftover from it being addressed as the 30th Space Wing, and in any material you would see it both with and without the 'the'.
The 30th, like its sister Wing, the 45th, took their numbered names from Air Force groups formed during World War 2: The 30th Bombardment Group (Heavy) and the 45th Bombardment Group (Heavy) respectively.
The separation of Air Force from Space Force is not entirely cut and dry, as the Delta is still composed of nine squadrons for support and operations, the medical is still its own group but the other groups have become part of the staff agency.