Is that what you call the adhesive tapes for attaching the LCD panel to the cover? This is the part number: 13NR01V0T05011 https://www.ipc-computer.eu/asus/notebook/rog-gaming-serie/rog-zephyrus-s-gx502gv-az035t/part-45365354/nup Or simply consider replacing these with a double-sided tape of a good quality.
Considering your words about unpinning 11 screws and opening the back cover, you must be speaking about the small CMOS 3v battery inside the laptop. Have you measured it's voltage? Those symptoms may show up if this battery is emptying.
Hello there! Replacing the mSata SSD on this model is not that easy as changing the SATA HDD, but you don’t have to be a rocket scientist - simply prepare to turn more than 5 screws. "Step 1: remove the battery" "Step 2: remove the screw in the center and take out the optical drive" "Step 3: remove the two screws from the bottom door and take it down. Next, remove 3 screws holding the HDD, detach two cables and one screw for the Wi-Fi module and remove the RAM memory" And we’ve reached the halfway, some more screws ahead. "Step 4: remove 8 screws from the bottom case" "Step 5: get some plastic opening tool (or an old credit card) to detach bottom case from the palmrest. Be gentle enough not to damage two cables between them. 1. Detach speaker cable from the MB 2. Detach screen cable from the MB" "And here it is - remove the last screw and get the old mSata SSD out" Hope this helps you. Cheers!
The simplest thing you can do is to replace the motherboard with a newer one from the same N551 series model. Asus N551VW can generally be considered a good option for such an upgrade: (1) motherboard is exactly of the same shape (consider replacing the cooling system) (2) all I / O ports and connectors are located in the same places (keep your old chassis) (3) it is equipped with a newer (6th gen) Intel processor (VS the currently installed 4th gen) (4) GTX 960M graphics has a higher memory bandwith (VS the currently installed GTX 845M) (5) total costs make not more than £300 (new MB with i7-6700HQ from China on eBay), and can be decreased by selling the old MB, for example So, there are possibilities for improvements, but it all depends on how far you want to go with this.