Wouldn't the simplest explanation be that the left side of the bed should be lowered a little?

Is your z axis driven by a single leadscrew? Google x axis sag as I think this is what you are facing.

If you have dual leadscrews you just fix one and raise the other to tram the x axis to the bed.

If you have one leadscrew... Google x axis sag as I don't have much experience there

You mention that you used an indicator? Is it applying force? Does your bed or you X axis deflect?

Am I stupid? Tried leveling by hand and now I'm getting these weird results again as if the glass bed is higher in some spots..

https://i.imgur.com/ewmkeQJ.png

I've never gotten these values to be close to each other (less than 0.5 difference)

edit: I don't get it.. the glass bed is perfectly level by itself. How can the printer read high spots on it?!

So you've used one of those mechanic leveling tools to manually set the screws so that the bed is the same distance from the nozzle in all 4 corners, and the automated probe is telling you that it's 1.5mm off from left to right? That's pretty weird.

Someone else mentioned there being flex/deflection in things, and I think that's something I'd look at first. But I'd also look at the sensor and see if there's a reason it would do that. Is it still the stock black or blue sensor? I never had problems with mine, but I've heard a lot of complaints about them, mostly that they're not accurate, especially on certain surfaces. Since they sense metal, maybe your bed has extra metal on one side vs the other?

I'm just spitballing here because it's weird enough that I can't really imagine what's going on.