Separate battery, screen and back-glass guides exist for the Pro Max; replacement display behavior can depend on Apple calibration.
What to check before buying
Display
The display guide calls for new screen adhesive and discusses post-repair software behavior. A quote for a damaged screen should identify the replacement part and finishing step.
Battery and rear glass
iFixit provides Pro Max-specific guides for both. The back-glass procedure also requires fresh adhesive; smaller 15 Pro parts are not assumed to fit.