How to restart after effects using a script?

app.quit() will save your project if needed and close After Effects,

but I don’t think you can execute any code after app.quit() to relaunch After Effects. 🤔 🤔

app.quit()

No. Scripts happen within the AE process, not independent from it. Once you terminate the program, scripts cease to function. Whatever you have in mind will require to be handled at the operating system level e.g. using Windows ' scheduler to relaunch the app. At best you can create a script button that calls these external processes, but terminating a program blindly can always have ill side effects, of course, like config files not being saved or getting damaged. The whole idea sounds weird, to be frank.

Mylenium