Photoshop saving dark images on Surface Book 2

Again - view it in properly color managed software. Not Windows Photos, not MS Edge.

Photoshop displays correctly, assuming your monitor profile is valid. That's what a calibrator does for you.

Not edit lighter, but view it correctly. Most major web browsers are color managed today - with the exception of MS Edge.

Getting a screen to print match is a different problem. Put very simply - if your print is too dark, then your screen is too bright. You can't change the color and brightness of paper, so that's the reference you calibrate the monitor to. You want monitor white to match paper white. It's just a visual match, the actual numbers will vary with circumstances.

On a slightly more advanced level, you do the same for monitor black vs. maximum ink on paper.

It's entirely possible to get an almost perfect match between screen and print. What you see is what you get. The trick is to calibrate the monitor to match the print, not the other way around.

This in fact confirms what Test Screen Name says. Yes, if you're viewing in an application that isn't color managed, shadows will appear darker and "crushed" with less detail. This is because all LCD screens have a native dip in the shadows. The curve drops towards black.

A color managed application, using a valid monitor profile, will correct for this and produce a linear on-screen response. Thus the file is represented correctly on screen.

A lot of people misunderstand what color management does, and why there should be a difference on-screen. They think a monitor profile is about correcting the monitor, and so everything should display correctly. But that's not how it works. The monitor profile is just a description, that the application uses to do the correction. The profile doesn't correct anything. The application does. Or doesn't, as the case may be.

Windows Photos, if that's what you're using, is not color managed.

The color space is sRGB per my workflow. The image is darker in all apps. From the windows photo viewer to, Google photos, Instagram, Facebook, and the Mac photo viewer. This is happening on all images since I started working on the surface book. 

Hello, do not forget that the surroundings of the image influe on its perception: the white around the second image make it look darker than with the dark grey background of the first one.

to me, the second image looks lighter in the light areas... Is there a different gamma?

I also wonder which app is used to open the image.

Did you look in Bridge?

A common problem is viewing final images in apps that aren't colour managed, so not capable of showing accurate colour, then feeling that Photoshop is the one that's wrong... So, to check on this, what is the app used to view the second picture?

If you want to check if the colour is accurate, re-open in Photoshop.