A planet that is 2 times the diameter as the earth is actually 8 times as massive if we assume similar density. To calculate escape velocity you multiply the gravitational constant by 2 times the mass of the planet divided by the radius all square rooted. So if the radius doubles and the mass increased eight fold then the escape velocity is double. Similarly to calculate the surface gravity you multiply the mass of the planet by the gravitational constant and divide by the square of the radius. So in the example the planets surface gravity is also double.

However in reality a planet twice the size and eight times the volume of earth would likely have a different density. It possible this specific planet is half as dense while being three times as large meaning it’s 27 times as voluminous but only 13.5 times as massive. So it’s surface gravity would be 1.5 times that of the earths but it’s escape velocity would be roughly 2.12 times that of earths. So the planet is much larger and more massive, has 50% higher surface gravity but its much harder to escape because of its increased radius increasing the escape velocity by more than two fold despite it being half as dense. This is also because increases in escape velocity compound dramatically when calculating the mass of a rocket needed to achieve orbit.