ok, here comes the answer you didnt ask for
if you use adobe/davinci combo, go windows and buy nvidia (2070/2080 or if enough cash Titan RTX with lots of memory. Davinci is going to benefit a lot from more memory, for adobe 2070/2080 is the sweetspot). You save money, you save on hackintosh tinkering and most importantly you save TIME.
for fcpx its macOS and AMD. best bang for buck is regular 2x580 or preferably Radeon VII (mem/core). Davinci also likes Radeon VII a lot (memory). You have to live with the noise or tinker. 5700xt possible, but its not running to full potential or RDNA architecture not as good in fcpx?
if you want to do adobe in macOS, you sacrifice time/money twice, amd architecture and not good enough metal optimization (adobe/apple)
you didnt mention input formats so I assume no RED footage etc, just regular h.264/265 and Prores mix
Radeon VII is actually not "more gaming focused card", but as AMD had nothing for that segment at that time they decided to take this workstation/server part and sell it as gaming card. Its pretty powerfull.
Radeon Pro W5700 seems more like slowed down version of 5700XT, but with double memory. Complex projects like more memory, but its slower overall. i would say its the same performance. your decision if its worth the money difference for you for some reason
Im running 5700xt for fcpx just fine, although 2x580 seems to have similar speed results (i have 5700xt instead of 2x580 only because windows 4k gaming). If i was willing to give that kind of cash I would go VII. I dont really see any other rational choices.