Blacks crushed, highlights overblown, brighten levels?
 

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As you can see in the picture, this was a pretty horrible scene where the person recording is filming inside a dark room while pointing the camera to an open door letting sunshine in. My histogram already shows that some of the highlights are getting clipped on the far right side of it while at 100 brightness level, but the blacks still look crushed and have 0 detail in them. I CAN see detail if I turn the brightness up to 120 such as the guy on the bottom right now having a white shirt on:
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I couldn't take a screenshot of the screen on the computer I'm using, the button/shortcut wasn't working, so I tried to use my phone to take a picture of the screen, which doesn't really show difference well, but in person it's pretty huge.

The problem is that MOST of the tape is like this, filled with a ton of scenes in poorly lit areas, but also has a lot of outdoor, bright sunlight scenes spread throughout the 2 hours on the tape. So I would like to just set it at 100 (actually like 95 seems to be the sweet spot to not clip most things) and just do the entire capture at that level, but the problem is that all the dark scenes will have crushed blacks like in the photos above.

Heck there's even this section in the tape where in the same scene, you can perfectly see the woman, but when they zoom out, she just turns into a black void lol.
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1 Second later after they zoomed out:
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Should I just do the capture at 100 level brightness and then go back for those dark areas and do another capture at a higher level? What do people usually do in these situations?

This is common with many amateur home movies. The highlights are lost due to overexposure and shadow detail also lost due to underexposure, both at time of shooting of the one scene. The camera can only capture a limited range of brightnesses. We cannot get those details back because they were never captured at the time.

But with good playback and digital capture gear you should be able to digitally capture in one pass all of what the original camera captured, without making multiple captures. Having made a good capture, yes we can sometimes digitally brighten up dark scenes at the expense of further washing out unimportant highlights.

Of course the ideal would be movies originally shot with better knowledge of things like lighting and exposure.

So it seems like people usually just set the brightness to a single level and unfortunately accept it will get clipped both in regards to crushed blacks and overexposed highlights? I was thinking of doing each scene separately at different brightness levels, but seems like that would take a lifetime as well and cause extra stress on my gear going back and forth/more captures.

As I said, normally with a good videotape capture system there's no need to make multiple passes to capture both the highlight and the shadow information.

But my comment about brightening up a dark portion of a shot relates to anticipating possible viewing issues when say people watch their TV or computer monitor screen in a very bright room where their monitor screen's dark detail is wiped out by the light in the room falling on the screen. But maybe this is a special case.

Your shot of the girl in the dark top was probably shot with a camera with auto exposure. When the camera was zoomed out, much more bright sky filled the frame so the camera automatically reduced its exposure to account for that. Now the girl was underexposed because the "backlighting" was brighter than she. The camera could not capture both the bright sky and the darkly lit girl at the same time.

But again the limitation was probably in the camera and the videotape. An experienced photographer would either stay zoomed in close on the girl to cut out most of the bright sky, use strong artificial lighting to better illuminate the girl, or if they couldnt do that, switch to manual exposure to correctly expose for the girl but overexpose the sky. Even though they use excellent equipment top feature movies shot outdoors still use artificial "fill" lighting to illuminate dark areas in the frame, to match the brightness of the background scene and sky.

Where high contrast can be a problem is with digitizing traditional "positive" or "reversal" film such as Kodachrome which exaggerated the contrast in a scene. That is where special "two flash" digitizing is used. Each film frame is exposed twice, at two different exposures, then the best of each shot is used to make a composite digital frame which carries all the bright and the dark information captured onto the film. This is often called High Dynamic Range (HDR) scanning. See the HDR demo section for this brochure on an expensive professional film scanner. https://lasergraphics.com/scanstation.html

Again ordinary home movie videotapes like VHS, Betamax, 8mm etc captured less dynamic range, making it normally possible to digitize the videotape well in just one well set up pass of the videotape.