The strut thickness isn’t foolproof my grand votlyager has electric doors, tailgate etc but just uses standard struts it actually has a second attachment along the top near a hinge that pushes/pulls the tailgate open/closed I’m sure many manufacturers do it the strut way but not necessarily all.
As for adding it there’s lots of 3rd party kits about to add it to your car not sure how good any of them are but it’s certainly doable but you’d be best off taking to motability as they might be able to sort it for you.