You are right - everyone has their own taste. I find these pictures you posted just a cute sketch. The photo under discussion here makes everyone think and look at that photo and discuss it. Thats what good art does.

The great American painter (maybe the greatest living painter) Jasper Johns became famous with his paintings of just plain American flags. But they were painted with such intensity that they made everyone intensely look at them. His idea was to make everyone look at something intensely - that everyone knew and would never look closely at because everyone knew the image so well. That makes a great work of art. It makes you look and think. That photo that started this discussion does that.

Here is a Johns flag. Hard to really appreciate it in a photo, but the painting is mesmerizing. If you see one of these flag paintings in real life, you cant take your eyes off it.

https://www.dw.com/en/the-works-of-us-painter-jasper-johns/g-53453933

Without buying extra software, for the smoothest possible tonality when editing JPEG color/brightness:

Either edit in Adobe Lightroom, which internally uses a 16-bit ProPhoto RGB-like workflow, then export to 8-bit JPEG in sRGB.

OR

Convert 8-bit sRGB JPEG to 16-bit TIFF in ProPhoto RGB.

Adjust the image as best you can, saving as needed.

Finally, convert the edited 16-bit TIFF back to 8-bit sRGB JPEG and export or save.

I just use Lightroom, which NEVER over-saves my original files. You can make all the edits you want, and export only a second generation JPEG.

The back-and-forth conversion helps to avoid stair-stepping and out-of-bounds color clipping. It is subtly better (you are NOT adding back anything thrown away at the camera, just being gentler to what you have). Results may or may not be worth the hassle, depending upon the subject matter.

I stay in manual mode, and I do review the exposure after the fact. I use DSLRs and a bridge camera (a lot like a mirrorless camera). I can't really check the image, histogram or highlight clipping ahead of time with my current DSLR gear. But it is easy enough to check ahead with the Sony. Autoexposure modes are pretty useless in these situations. These are some examples taken with a Sony RX10M4 hand-held at night. ISO ranged from 100 to 800 - well within the capability of the camera for good clean images. I've shot it as high as 3200 and was satisfied.

https://live.staticflickr.com/822/26097752007_e738dbca48_k.jpg_DSC2151-DSC-RX10M4--(19-02-18) hi res by Gene Lugo, on Flickr

https://live.staticflickr.com/4794/26097752107_3a97d64a0e_k.jpg_DSC2148-DSC-RX10M4--(19-02-18) hi res by Gene Lugo, on Flickr

https://live.staticflickr.com/812/39160278180_d9b5b4673a_k.jpg_DSC2155-DSC-RX10M4--(19-02-18) hi res by Gene Lugo, on Flickr

https://live.staticflickr.com/811/26097752397_156e43b650_k.jpg_DSC2145-DSC-RX10M4--(19-02-18) hi res by Gene Lugo, on Flickr

https://live.staticflickr.com/797/26097751937_06c119776d_k.jpg_DSC2153-DSC-RX10M4--(19-02-18) hi res by Gene Lugo, on Flickr

Take a look at this photograph: "The Extras, 2009," the seventh photograph on this page - https://www.lehmannmaupin.com/exhibitions/alex-prager6
(I'm posting the link, not the photograph, because I did not take it and do not have permission from the photographer to use it.)
There is something about it that I just can't put my finger on. To me, it looks unrealistic. I'm not talking about the scene or other "content" but the "qualities" of the image. I don't know how to describe it--like the difference between the photo of a building and the "artist's rendering." In a way, it seems almost like a drawing than a photograph.
How would one go about achieving this "effect," if that's what it is?
Does anyone see what I mean, or is it just my imagination?

Perhaps you folks can help: I have searched the internet, but cannot find an answer to my question, probably because I’m not asking correctly.

I am using an iMac (High Sierra 10.13.6) and Lightroom 6.0. How do I import photos into my Mac without them also automatically going into Lightroom? I’m assuming (hoping) there’s a simple answer.

I do not intend to upgrade to the newest operating system because I am still using some 16 bit programs, and I do not intend to move to the LR subscription program, so thanks in advance for not making those suggestions.

Any help that Mac users can give will be appreciated.

Your flash was powerful enough for the images that you posted here. In fact, it was too bright on the bride and groom in the last picture. Their flesh tones appear to be burned out on the cheeks. I would've dialed the flash back a bunch because to me--and this is just my opinion---I would rather be slightly underexposed on flash portraits. I can increase exposure, but once you've lost the cheeks and forehead, there's not much you can do.

If you want a more powerful flash than the SB-910, look for a used SB-800. I have 2 of them and they are the most powerful flashes that Nikon made (I believe more output than the SB-5000 is).