Do GFCI outlets require more than standard box volume?
A GFCI only requires the same fill as any other device. In your case with 14-2 one cable in one cable out and the device 4 current carrying conductors 1 ground ,x 2 device , clamp. 14 awg =2 so 2 x 8 or 16cu inch. 2 devices ? 20 cu inches?
There should be plenty of room, if you get excessive with your wire length that will quickly gobble up room, if your wire or pig tails are longer than 6” trim them back the next thing would be to make sure to make sure your wires are packed tightly in the box I have had people that try to put a foot long end and long pigtails in boxes and can’t get them in the box so length and arrangement in the box make a difference.
Although GFCI devises are bulkier than normal devices they require the same device fill as other devices unless marked by the oem and I have not seen that.