It really depends on what your wife's work entails. If it's something like video editing, mathematical work that uses all cores in MATLAB during computation (actual use of FFTs aka Fast Fourier Transforms), or CPU-based rendering (mainly those that don't fit into 8GB VRAM) then it's going to be different than GPU bound workloads , web browsing and Microsoft Word. Unless an application is well threaded and parallelized then there's not much gain from 6 cores to more cores due to Amdahl's law. That utilization rolls into the lifetime of the board, since if it's not 100% utilization it isn't going to heat up the board or the CPU nearly as much (for example, my Ryzen chips run ~10°C hotter at the same clock while running AVX instructions pegged at 100% usage).
If you're looking at buying from Microcenter I'm assuming it's the 8 core since the 12 core seems to be out of stock. The Aorus Elite should be fine for anything 12 cores or less in a well cooled case. I haven't seen anything suggest otherwise and $300 Asrock's Taichi and $300 Asus' X570-F STRIX + TUF Plus use the same powerstages more or less. The lifetime of 5K Hours for the Taiwanese Apaq capacitors on Aorus Elite (and most other boards of that price tier)
is at 105°C at a higher 6.3V voltage (if running 1.3V or so you are derating the capacitor so you get much more life out of it), the $300 Taichi has 12K hour rating "FP" Japanese capacitors with the same powerstage type. To put it into perspective, 10°C drop yields 2x capacitor lifetime (Arrhenius' law)
for electrolytics , keeping in mind these are solid capacitors. 365 days a year for 8 hours a day is around 3K hours. The Aorus Elite should be running something along the lines of 70°C or less especially with the 8 cores which means around 40-50K hours (4.5 years 24/7 or around 13 years at 8 hours/day)
at least assuming 100% load.
If you aren't going nuts with overclocking 12+ cores and PBO (to make use of all the power delivery and the debug features such as debug LED + clear CMOS) there's no motivation to buy Aorus Master unless you need 3x M.2.
As far as the RX 5700 XT goes, unless you're watercooling it with a non-existent waterblock or putting an Arctic Accelero Twin Turbo on it (takes up a lot of space) then you're better off waiting a month for the aftermarket cards.
If you're looking at $1130 I'd probably go with:
Ryzen 7 3700X $330 before bundle discount of $100 due to RX 5700XT + x570 board
: Aftermarket cooler such as the Scythe Mugen 5 Rev B or some other 6 heatpipe cooler $45-60
RX 5700XT + Arctic Twin turbo III or RX5700 XT aftermarket ~ $450 (build in ~$30-50 for the cooler)
2x8GB RAM 3200+ MHz CL16/CL14 = $65-$160
---> https://www.microcenter.com/product/...d32aesb---gray should be Micron E-die
---> https://www.microcenter.com/product/...2z3600---black Likely Samsung B-die , 3600C16
---> https://www.microcenter.com/product/...36beea---black Crucial 3600C16 can be B-die
--> https://www.microcenter.com/product/...-16gfx---black AMD-oriented Samsung B-die costs much more
Aorus Elite $200
Total ~ $1100 (1000ish before tax)
* If doing video-work , fit in a PCIE 3.0x4 SSD such as the Corsair MP510 (TLC NAND with large SLC cache and high endurance rating) or Samsung 970 Pro (MLC NAND for high sustained write)
* PSU + decent case can't fit into a budget like this unless you cut it down to a $350 RX 5700
Microcenter is good about matching Newegg/Amazon pricing especially if you're buying hundreds of dollars of components so if you see something you want in-store just ask for a price-match.