I guess it comes down to which software you use more and which tasks you are willing to wait longer for. The 8700k offers the best single threaded performance and can overclock the highest, so if your priority is the adobe stuff, that might be the better choice.
The 7820x kind of sits in the middle with better per core performance than Threadripper and more cores than the 8700k but still not nearly as powerful in multithread as Threadripper, isn't as good an overclocker as the 8700k and is on a very expensive platform. With Coffee Lake refresh chips on the way soon with 8 cores eg. the i9 9900k will basically be the 7800x but with better clockspeeds, the 7800x might not be really worth considering unless you need a computer right now and you can't wait a month or two.
Threadripper offers you the most cores and threads which rendering tasks like, but you might take a bit of a performance hit on things that benefit from single core performance. You can overclock Threadripper to help alleviate that to an extent so long as you get a motherboard with beefy power delivery and have very good cooling. If the tasks that scale up to 32 threads are your top priority, then Threadripper is the best choice for you.
At the moment there isn't one CPU that can do everything you want the absolute best (unless you want to pay through the nose for the i9 7980x or 7980xe and overclock it) so it's up to you which aspect you want to prioritize. Going the Threadripper route might be best overall unless you very heavily use software that favours Intel and per core performance quite heavily and aren't willing to take a bit of a performance hit there.