The Sun’s radius is ~696,000,000 meters, so the surface area of a perfectly circular cutout would be 1.5218e18 square meters. An article I found says that cardboard used for packing is about 0.35-0.4 kg per square meter, so taking an average of 0.375kg/m^2 gives a total of 5.7069e17kg. This is about the same mass as 40% of all water on Earth.

https://www.amazon.com/White-Corrugated-Paper-Sheet-Pack/dp/B08D2GT19P

A 10 pack of “20 x 30 x 0.16 inches;” cardboard weighs “6.4 Pounds”.

10x30x10 is 6,000 square inches, or ~3.87 square meters. 6.4 lbs is 2.9 kg. So figure ~0.75 kg per square meter of corrugated cardboard.

https://en.wikipedia.org/wiki/Sun

Its diameter is about 1,391,400 km (864,600 mi), 109 times that of Earth.

Area is r² times pi.

$ maxima
(%i1) float((1391400*1000/2)^2*%pi);
(%o1)                        1.520526100532553E18

So that’s a mass of about 1.5 x 10¹⁸ kg for the cardboard cutout.

https://en.wikipedia.org/wiki/Earth

Mass: 5.972168×10²⁴ kg

Earth has about four million times as much mass, so the Sun cutout would have about a quarter-millionth Earth’s gravitational pull.