If you just want a 7PRC, obviously, go ahead and get one, but I do have two thoughts.
First, you said you don’t have time to go to the range often and fidget with stuff, if you don’t have time to practice that much, are you actually going to be capable of shooting at longer range anyway? I like the idea of shooting at longer range, and I want to be prepared for that equipment wise, but I question whether someone who can’t practice often is going to be able to take advantage of the incremental difference the cartridge has to offer in the first place.
Second, I have literally never seen a box of 7 PRC ammo in a gun shop. Never. I realize I live in a bit of a backwater, and you can buy online from most places, but if your goal is to be a one gun hunter, having that one gun be limited to an uncommon factory offering, even if it might increase slightly in the future, would be a dealbreaker for me. If I have only one option, I want it to be something super standard. That could be points against the 7PRC, or it could be points for keeping your 3006 intact as a back up.
Copper at longer range seems to be anemic in a lot of cases with factory ammo. I’m sure a 7PRC would do fine, although I have yet to find a rifle that likes the hornady superformance stuff that you mentioned. I think some of the conventional wisdom on calibers goes out the window as soon as you stipulate copper. I did a bit of a rearrange of one of my rifles this past year specifically to shoot copper, and ended up with a regular old 270 Winchester. Factory-loaded Barnes LRX maintains 2200 ft./s to 520 yards at 7000 feet elevation, and in a pinch I have ammo options in nearly any mom and pop store in the country. All without having to go the custom or semi-custom gun route, so I could put my extra budget into a more reliable scope and plenty of practice ammo. Given your specific goals, were I in your shoes I might at least entertain the idea of getting an eight or nine-twist 270Win barrel spun onto my existing rifle. If you do go the 7PRC route, I’d personally want to keep the 3006 intact as a back up in case I have problems finding ammunition in the future.