how to secure NativePhP Desktop App

hi, i built a desktop app using NativePhP and local sqlite database, now im trying to secure the app from steeling , like if a client ask for trial i will only give him some period before the app wont open again .

second , how im gonna secure the app in the future to prevent the client copying the app files to another computer and make it working again .

if one of you guys implement this idea or have an idea how to do it please tell me or give a resource .

thank you.