US passport user flying SAS business class on CPH-ARN for a ticketed itinerary that goes CPH-ARN-EWR while having only standard luggage to check-in within the included baggage allowance for the ticketed itinerary? Then 90-100 minutes before check-in is the earliest I would get to CPH when having an 8am departure in SK premium cabin on the CPH-ARN flight.

3 hours before for such a trip as above? Way too early every day of a normal week out of CPH for capable, fully mobile adults. 3.25-4 hours before the CPH-ARN flight would be mad (unless there are serious flight disruptions and for some reason needing to deal with the ticketing service line at the airport on arrival).