If anyone finds a solution Id like to know. Even after disabling all services in task manager, after a minute or so it restarts on its own without any notice.
You need to open the services menu in task manager and individually change startup type to manual for ExpressVPN App service, System service, as well as VPN Service.
Once you’ve updated the startup type, end the service from the service menu and then it should keep ExpressVPN from launching on its own.
This worked after a computer restart! No ExpressVPN background services automatically started on a fresh boot. And no issues running expressvpn with manual triggers. Background processes will still be present after launching/closing ExpressVPN, but stopping them seems to keep them closed. Thanks my dude.