Yes, League changing to x64 has had a large effect on scripts. In the past, scripts were typically written in x86 assembly language. This made them relatively easy to write and modify, but they were also relatively easy to detect and ban.
When League changed to x64, it became much more difficult to write scripts in x86 assembly language. This is because x64 assembly language is much more complex than x86 assembly language. As a result, script developers have had to switch to writing scripts in other languages, such as C++.
Writing scripts in C++ is more difficult than writing scripts in x86 assembly language, but it also makes the scripts more difficult to detect and ban. This is because C++ is a higher-level language, which means that it is more abstract than x86 assembly language. As a result, it is more difficult for anti-cheat software to understand what C++ code is doing.
As a result of the switch to x64, the number of scripts in League has decreased significantly. However, scripts are still a problem, and Riot Games is constantly working to improve their anti-cheat software in order to detect and ban scripts.