I prefer a trifold soft cover on my 2020 5.7 bed. Very easy to remove when needed (I can remove and carry it with no help, easier with the wife to square it up on reinstall.) It is very water resistant, some minimal leaks from the tailgate area. I did not buy/install any kind of tailgate seal for my truck. If it has to be watertight I use very large trash bags, and or plastic tubs. I have the flexibility to fold and store the cover in the bed or the backseat (requires help and some adjusting, not recommended.) My cover also requires the tailgate to be opened, my tailgate automatically locks with the door locks. Not a high-security device as noted, but it keeps the honest folks out, and if someone wants in as noted a sharp instrument, and they can see that most of the time, just air in the bed. But hopefully minimal damage to the truck. FYI, I have the Truxedo Trifecta 2.0 cover, I would buy the same top again if required, it fully meets MY needs, but your mileage may vary.
For the snow question/problem: When the snow wizards make a prediction of snow, I take the cover off and store it in the garage/house. I have had it snow as a surprise and my top has handled the load well. I promptly remove the snow with a broom, and then take the top off and place it loosely folded in the garage to dry. Since it is a pickup truck and my primary transportation. By having removed the top as a precaution also allows, the snow build-up in the bed, to give me free weight, adds traction, and reduces the tendency to spin due to the lack of weight/mass in the bed. By the time the snow melts the roads have been plowed, sanded and are in the process of clearing.
BlueHemi1500