i having trouble starting the timer at the right time

Autosplitters exist for some games, which pretty much do what you are saying.

If that isn’t a thing, you can always just retime.

A memory or scripting based autosplitter will always be better, but if you have consistent visuals to split on, and a bit of time to tinker, you can try out https://github.com/Toufool/AutoSplit which is a generalized image-based autosplitter.

Does anyone know how to make LiveSplit automatically split characters in Resident Evil 4 Remake? I want it to automatically split characters when entering a specific area or boss area.

If your game isn’t supported, LiveSplit can’t detect when to start automatically