Pump the brake pedal several times then try turning the tires by hand. If they’re hard to turn remove tires and pump the brake pedal again several times. Now crack open the bleeders. If brake fluid squirts out the problem might be with the brake hoses to the calipers.
Over time these hoses can deteriorate internally where a hunk of rubber delaminates and hangs inside the brake hose. This hunk of rubber can act as a check valve. That is, when you apply the brakes the pads clamp the rotors. But when you release the brakes, that hunk of rubber prevents the hydraulic pressure from releasing the caliper pistons. So the brakes remain applied.
Tester