A mint device will still always get you a better resale value down the road. It's worth the trade off IMO. Cases also make a device feel better.
I have seen you comment on resale before, but highly doubt your conclusion. How many devices have you sold on the resale market, because I guarantee you if you trade it in, it will make no difference at all between a mint device and a gently used device. And I sincerely doubt it makes a difference on the open resale market. Over the years I have sold at least a dozen apple devices on the open resale market. People there shop for value, capacity, maybe power cycles, but never have I been asked for 'mintness.' They ask if there are major dings, but eh, no one believes mint versus gently used.
But let's say it makes any difference at all, it will be at most a few bucks, and certainly not worth at all the cost in cases and time and anxiety that you have expressed here. At least not to me, my time is valuable to me.