Replace the jack wires going to the LED strips. Or look for the one bad jack wire going to the LED's and fix it. Use a volt meter on ohms to find the bad wire.
Back - light problem. Check and replace damaged component/s at its back-light inverter board, or replace this board as card basis. If you wish to get some details; check the site linked here. Surf the site with patience. Pull up older posts. It will be best to replace the inverter board as card basis.
http://electronicshelponline.blogspot.com/
Some model sets; especially LED back-lighted types; the back-light inverter circuit will be part of the main power supply board [SMPS]. In such cases, the power supply board might need replacement.
It can't be done. The DVD remote will be single frequency for that device only and the LG remote for that LG Blu Ray (or series) only. Companies don't make cross-control between makers easy. The only exception is cable and satellite boxes to allow their remote to also control the television.
If you have lost a remote or it doesn't work, this is the answer
https://www.fixya.com/support/r29872378-universal_remotes_no_facsimile_remote
..
It appears to be a model made for the India market.
https://www.google.com/search?q=lg+dsi+8555+manual
This is the only service manual that is related. If the display is not working, look on the back of the display board for a split or bulging electrolytic capacitor.
Encompass Parts
https://research.encompass.com > ZEN
PDF
This manual was prepared for use only by properly trained audio-video service technicians. When servicing this product, under no circumstances should the ...
109 pages
That will show in your network settings on the tv screen under manual entry network, or automatic entry try both and then write them down when it shows them.
There may be a backlight issue. Some of the LEDs may have failed causing the LED to stop working at the correct voltage. This will tell the main power supply to switch off as there is a problem.
I would ask LG support.
https://www.lg.com/uk/support/contact-us/