apologies, english is not my native ..
dug into LOL more than a decade ago with a few mates to back an api/bot/site, parsing the keyframe and chunk formats within a week of spectator launch to automate timer callouts for jungle camps through fog of war due to the observer delay being less than the respawn time and so-called « auto-shoutcasting » for matches implementation when we were maybe 11 years :)
there are a number of difficulties these days (ive not played in years but work in the industry and do not touch these due to legal risk particularly REing competitor code)
from kernel anticheat being a requirement and packman before that - this article was written during covid so predates vanguard but contains packman -
legality - RE is « forbidden » - bannable so in which you do not want to lose your account in which you have spent tens of thousands of hours or more, breaking authentication and DRM flows is [DRM, auth handshake, protecteions] illegal in USA -
entire obfuscation format and flow changes with every patch; you have to repeat the work every hotfix + patch (and it isn't just a new xor key) - the re implementations would probably need to be realised every week or two - annoying - this is likely one of most tedious bits