My experience is the same as that of @Marie13.
When I am diving an unfamiliar site, I may well seek out a buddy who is experienced there. That person need not be a DM. While a DM can be a guide, a guide does not need to be a DM.
Around here, DMs tend to primarily assist with instruction. Once the course is finished, their DM role is finished and I go back to diving with them as friends and dive buddies.
Never understood why some feel that a DM must be in the water with them at all times...
It’s the warm water vacation occasional divers who seem to have that attitude. I once had a moderately experienced diver who was a warm water vacation diver who told me I didn’t know squat since I had never dived with a DM. I told her she wouldn’t know what to do being dropped on a Great Lakes wreck with no DM. Swim around on your own. Oh, the freedom!