Actually there's a movie on Assassin's Creed concept though its not about this exact plot.
You can check it out. It didn't become a blockbuster but as an AC fan, I loved it and I'm still waiting for a second installment.
https://www.imdb.com/title/tt2094766/
Also, I didn't understand one thing. Yeah you said you did it hardly but then why it is 90% rather than just a 60% or 70%?
The memory sync depends on the optional objectives only. No matter how hard the mission is, I can get 10% memory synch if I follow them.