Recently I was taking photos of our grand kids jumping/swimming. Kept adjusting settings. Bump up the speed from 250 to 500 to 1000, Bump up ISO,
lower the F stop. Never could get a good picture. Either too dark or blurry or both. Couple more just washed out and just way too soft. Not a keeper in the bunch
I was using a 18-250 sigma lens, 3.5-6.3 on my Nikon 600.

All still shots were just fine.

Could be my ability to adjust on the fly. Just a very slow focus lens

Soooo I thought to myself. Get a fixed f stop lens (the lower number the better) that I don’t have to worry about and get a zoom with some reach.

I’m basically an advanced amateur at this. Been at it 60 years tho. therefore,
after a few more hours of reading UHH and other sites, I purchased this lens from Nikon…

I read on UHH some folks call this a prime lens since F-stop is fixed…
I didn’t think a prime lens could change from 24mm to 70mm…like I said Im an old amateur at this

It's a damned good lens, but as you suspect, it is a fixed maximum aperture zoom, not a prime lens! Primes have ONE focal length. (Lots of folks get confused over this, or loose with words, or both.)

The 24-70mm f/2.8 is the classic professional, fixed maximum aperture, wide angle to short telephoto zoom lens. I call it a "rubber normal." It is the most used zoom in my kit. (I use a 12-35mm f/2.8 on Micro 4/3, which has the same field of view range, at 1/4 the weight and half the cost.)

Pros call the full frame 24-70 the middle range of the holy trinity of zooms... the wide one is either 14-24mm or 16-35mm f/2.8. The long one is 70-200mm f/2.8. You can get longer zooms, and zooms with a wider range of focal lengths, but these three are the best you can get for most uses other than field sports and wildlife work.

Zooms with fixed maximum apertures are larger, heavier, and more difficult to design than zooms with variable maximum apertures. They work great in a studio with all manual flash equipment, since you can zoom without changing the exposure if you're working wide open.

But a variable max aperture zoom can be sharper, better corrected from distortion, CA, etc., at a given price point, and lighter/more portable. The annoying part about the variable aperture is that the dimmest aperture is at maximum magnification, where you need the fastest shutter speed to avoid camera shake.