XPS 15 9500 Display

The screen is cracked in the lower left corner and the display assembly will need to be replaced.

To force  a power off, unplug the system and hold the power button until the power cuts out.

The thing is that the screen has no cracks nor scratches on it though. 

Okay so I checked the diagnostic LEDs and it appears to be an issue that I can only resolve through being able to look at a screen to which I can't do.

However, I'm a little bit confused on the screen situation. Firstly, I've been looking online and I can't find a seemingly official website that provides the part to replace. Do you know of a link or resource for that? Secondly, if this was just a screen issue, why doesn't it allow me to use an HDMI cable to see what's going on? The computer components themselves are still intact and connecting to an HDMI has worked before as well.

The thing is that the screen has no cracks nor scratches on it though. 

Here's the inside. I don't know if you can see if there is an evident issue but I do not believe that it's a screen issue and more so a component issue because of the blinking light.

If you mean the front glass panel, that may well be, but the LCD panel itself is clearly cracked.  

That is impact or stress cracking from the bottom left corner.  On these systems you cannot replace just the LCD in the display - the assembly is fused together and the entire display assembly needs to be replaced, whether it's just the front glass or, as in this case, the LCD display element itself that's cracked.

Here's how to interpret the diagnostic LEDs

https://www.dell.com/support/manuals/en-us/xps-15-9500-laptop/xps-15-9500-service-manual/system-diagnostic-lights?guid=guid-42ce74aa-11a6-4abe-a583-35962b510a4a&lang=en-us

I didn't replace the battery immediately due to shipping + equipment delays, so I don't know if it was swollen at one point or not. Right now, the original battery looks perfectly normal/not swollen.

As for the panel, my panel is UHD and the website (and other websites) have extremely bad reviews claiming that they are a scam while others say they aren't. At this point I'm not sure investing $450 into a new display which may or may not work for the computer is even worth it. Should I just buy another laptop?

Thank you for your help so far though. 

You'll likely find those mixed reviews everywhere;  the important thing is to verify compatibility before buying, as I can almost guarantee you a number of the bad reviews came from buyers who didn't do that, and did not understand that most sellers of display panels will not take returns.

I would also verify that the panel is the only faulty part of the system.  If it is, the cost of even an UHD screen is just about 20% of what an equivalent replacement XPS 9520 would cost, so the replacement, while not inexpensive, likely still makes economic sense.  On an Inspiron or G-series it probably wouldn't, but on an XPS it is still a fraction of the cost of replacement system.

If the display is not recognized -- and this one is sufficiently damaged it may not be (which may be  part of that flashing pattern you're seeing), the system won't complete powerup self test, so the external display will never be activated.

Which panel you need depends on the display type you have.  

If it's FHD, 

https://www.parts-people.com/index.php?action=item&id=34047

If it's UHD,

https://www.blisscomputers.net/new-dell-xps-15-9500-lcd-assembly-uhd-3840-x-2400-touchscreen-silver-w9f11-247452/

There are other panels depending on whether you have or not a touchscreen system.

Was the original battery swollen before you replaced it?