It's all of the above. You can never stress cleanliness enough. Always ride with clean shorts. Use good hygiene "down there". I can get away with cheap shorts for short rides buy use good ones for long, hard or very hot rides.

The saddle must fit you properly. This includes both it being in the right place (the bicycle fit) and being right for your butt (a completely personal issue). Until those are right for you, asking your shorts to be comfortable is asking a lot. When all the fit issues are right, many of us need very little between our butts and the seat most of the time. But there is no shame in using any of the many chamois fats. And if things get really bad and you still have to ride, there is always the super chamois fat that works when all else fails - Bag Balm; that formulation for cow udders in the early days of mechanical milkers. Worked so well that the cows would willingly walk up to the bovine torture machine and yield their milk. (Didn't take long for the inventors to improve the comfort level of those machines a lot but by that time, the farmer's wives knew well how good that Bag Balm stuff was for all sorts of human issues.) Any old-school pharmacy will have Bag Balm in green can with 1920's styling. $8 give or take.

Ben