The variation in distance from the Earth to the sun is not the cause of the seasons. In the northern hemisphere it is summer during aphelion (farthest distance from the sun), but in the southern hemisphere it is winter. And both hemispheres are at the same distance from the Sun.
The Earth describes an elliptical (although almost circular) orbit around the Sun. At aphelion we are 152 million km and at perihelion, 147. Those 5 million km have no perceptible effect on the seasons. If it does affect anything, the buffering effect of the atmosphere more than makes up for it.
The cycle of the seasons is given by the inclination of the terrestrial axis.
On the one hand, due to the inclination of the Earth’s axis, the Sun irradiates the northern hemisphere for more hours per day in the months of June to September.
In the image below you can clearly see that the northern hemisphere receives more sunlight due to the tilt of the axis. The equator is tilted, exposing the northern hemisphere mostly to the sun, which receives radiation for more hours and with less inclination than the southern hemisphere. Therefore, it is summer despite coinciding with aphelion (farthest distance from the sun).
On the other hand, also due to the inclination, each ray of the Sun during those months ends up being distributed over a smaller surface area of ​​the Earth. Therefore, the same amount of energy is distributed over a smaller surface area, resulting in more energy per square meter.
In the southern hemisphere, the exact opposite happens. During those same months, the rays of our star hit more obliquely. Each sunbeam is distributed over a larger area delivering less energy per square meter for less time throughout the day, therefore it is winter.
When the Earth reaches half a turn in its orbit, it is on the other side of the Sun. Therefore, it is the other pole that is most exposed to solar radiation, with which the situation is reversed.