And yes! The true ending us so worth collecting everything. Technically you don't have to collect everything, I calculated Lilly's score at 100 at about 200 collectible (memory sticks and documents) but there are some stuff that is essential if you plan on finishing the game on Nornal node, at the end it gets Sekiro difficult and it was such a pain for me as I had not upgraded my health to full. Also remember that there are other healing items if you hold up on the Dpad, they saved my ass in the last few fights.