Liquid damage; potential black light issue, replace LCD assembly?

Hello everyone! Thank you in advance for reading and answering my issue!

I have an iPad Pro 12.9 256GB (4th gen). About 16 months ago, I spilt coffee in my backpack and damaged my iPad. At that time, I immediately took apart the iPad and cleaned everything with high quality alcohol and let it dry for about a week. It honestly seemed like there wasn’t too much coffee inside of the device - so I had hope. However, when I finally turned it on, the screen was black. When I connected it to a monitor, the device still functioned and the touch screen/audio worked fine. After some research, I considered buying a replacement screen at that time but with them being ~$300 CAD and a chance of the water damage leading to the device becoming more damaged as time went on, I decided not to buy one in the off chance that eventually the iPad would go kaputt. Instead, I just cried and bit the bullet on a new iPad.

Fast forward to a year and a bit later (now), I am now finished university and have some free time to re-visit the device. Now when turning on, I can see a faint image of screen in addition to a few black bars going across the screen, suggesting the backlight is toast but also some potential LCD damage? Additionally, the Face ID camera fails and prompts an error. Once again, the audio works, the battery doesn’t get hot with extended use, and there seems to be no other issues.

Therefore, my question comes down to whether this can be fixed by replacing the LCD assembly, whether it is likely that the damage remains in the logic board, or if it’s not worth it at all to spend the money trying to fix it. Additionally, I already have a new iPad, so I have nothing to lose experimenting. I would love to spend the time learning how to repair devices and would consider purchasing a soldering kit if that can potentially solve the issue.

Best case scenario, I can keep this broken iPad as my new Netflix machine and sell my newer one for $1500! Win-win! Worst case scenario, I’m left off where I started.

Once again, thanks for reading!