I suspect that any POD which allow a German victory would leave the SS much weaker than it was at the end of the war, and I could see SS go the way of SA in the power struggle after the death of Hitler.
Also SS doesn’t really compare to the marine corps, it compare better with the Republican Guard of Iraq or traditional Royal Guards in different European countries. It’s a common structure in authoritarian regimes as a way to protect the supreme leader from coups. But with the leadership of SS playing their own power games there are fewer reasons to keep them around.