If a 'top-freezer' refrigerator's freezer door pops open when the larger fresh food door's closed, it's actually a good thing. That tells us the seals are in great shape and sealing well.

Some freezer door 'pop' is unavoidable because the bottom door's so much larger than the top one. Door liners are more lighter than your earlier models.  The two compartments share the same air via a duct between them, and that compressed air rushes up into the freezer compartment and can 'pop' the door.

To improve the situation, apply a few drops of oil (three in one - NOT WD-40) to each freezer door hinge pin. (Even better: if you can, pull the doors and coat the hinge pins with petroleum jelly). This will help the freezer door swing back closed by itself. The freezer door usually stays ajar because it's binding a bit, and that's usually caused by it's swinging 'dry', with no lubrication.

You can also try adjusting the refrigerator legs to make the refrigerator tilt back a bit to help cushion the slamming of the door.

It’s also a good idea to ‘kick’ the habit of letting the refrigerator door close hard.