Is a built-in oven easier to maintain than a standalone one?
I'm not aware of any practical difference between the two in terms of maintenance, except that servicing a built-in stove and oven might be harder because the underside and rear are not easily accessibly.

Otherwise, the only reason I've ever needed to move my free-sanding oven was to clean under/around it. If the built-in stovetop is properly installed and sealed to the counter, cleaning under it should never be an issue.