Content undersexposed when added to Premiere

That would be a color management issue.

In Premiere, go to the Color Workspace, Lumetri panel, the SETTINGS tab ... the one named Settings.

Set your viewer gamma to 1.96/QuickTime, and things should look similar inside or outside of Premiere on your laptop if using QuickTime Player or Chrome or Safari.

And while that will make things more consistent on your laptop, understand ... Apple on most of their rigs uses a non-standard display transform, essentially a gamma of 1.96, with an also not quite accurate remap of Rec.709/sRGB color to their monitor's P3 color space. Which is why the change in apparent brightness and saturation.

On the Apple rigs with "Reference Modes", when the monitor is set to "HDTV", you would get proper broadcast/international standard display transforms similar to gamma 2.4. Without the problems you are having.

So the change I give you above will get your inside Premiere view to match your system outside of Premiere. It will, unfortunately, be too dark and oversaturated on any non-Apple system (Anddroids, PCs, broadcast spec systems) and all Macs with Reference modes.

What a joy, right? 

I would simply add that all professional media for Rec.709 is graded in a semi-darkened room with gamma 2.4. So every pro content you watch on that computer was graded 2.4. You aren't seeing what the colorist saw when grading. Has that been a problem for you?

Probably not, as none of us ever see exactly what the colorist saw. We only see their stuff on our screens. Which are actually all over the place.