Yes, enlisted ranks exist. That was not in question.
This was about having a dedicated, marine combat medic as a permanent role in a small team of 10-15 people. There are already enlisted medical specialists serving alongside these would-be marines. That was the point.
A medic that isn't trained to operate in combat is going to be a liability to those around him.
Absolutely, which is exactly why these small marine detachments would access to a whole-ass starship medical department who are specialists in that particular thing.
The only real difference here is rather than having these marines are a separate branch with their own redundant roles for everything, they can utilize the specialists available.
Isn't half the point of this force that they can operate for extended periods of time off the ship?
Also, the idea that only doctors or nurses could do that sort of work is the same intellectualist-elitist BS that permeates much of Star Trek (all of modern Trek and parts of TNG in particular, but not DS9, VOY or ENT) and is even worse in the fandom.
I agree with you that in like, real world terms some of this is... suspect. But i'm trying to create something uniquely Star Trekian. But i'm also trying to look at it in terms of scale while also trying to make this fit (mostly) into established Star Trek.
Yeah, but in order to improve on what we see on the show, then IRL standards should be applied.
However, you do have a point to a degree, which is why I've been trying to point you away from the "all soldiers" Marines model and over to a more multi-purpose unit modelled on the Green Berets (which have a fairly Starfleet-ish mission profile in many ways), Navy SEALs and the like, because they can be combat-focused but still politically palatible in a way that overly and exclusively military units wouldn't be.
We know Starfleet ships don't carry around huge contingents of soldiers. They... could potentially carry around small numbers of them. The way that Starfleet tends to operate is largely individual ships out in the far flung reaches doing whatever it is they do. Having a completely and totally separate military unit with entirely it's own specialized people just doesn't really make sense in that context.
Now what I *COULD* potentially see, and perhaps something that fits in even better with Star Trek, is that the marines would pull some kind of duty when not actively deployed.
Again, as noted above, that's why them being combat soldiers only doesn't make sense, but having them be made up primarily of specialists who are extensively trained in both combat and a specialism that would be of use on board makes more sense.
So that enlisted medical lady from TNG could have potentially actually been the marine medic, working in sickbay because their marine detachment wasn't being used for anything. (she's not, I know, it's a theoretical).
Actually, all the female named medical personnel from TNG (certainly the ones that had dialogue) were officers (Crusher, Pulaski, Selar, Ogawa), the sole enlisted medical technician was Crewman 1st Class/Ables'man Simon Tarses, one of the ship's pharmaceutical technicians from The Drumhead, which seems like more of a "green side" role compared to other unnamed technicians that acted as first responders or assisted in surgical procedures.