There is no standard - other than what is confirmed in the reservation. That the room may be reasonably large at 100 sqm , does not mean that there will be 2 or 4 beds or that the hotel will provide additional bedding at no charge.

The max occupancy can be based on factors other than number of beds and just details the maximum number that can stay in the room

The one place that will be able to give you a definitive answer on what the room has and what can be provided is the hotel itself

I suspect that you may be better served by 2 rooms if you have 4 adults wanting beds