Your MoBo has M.2 PCI-E 3.0 (Gen3) slot, making the 990 Pro PCI-E 4.0 (Gen4), waste of money.
Also, the very store link you liked for SSD, there is heatsink variant as well, which actually is 5 bucks cheaper than the one without heatsink. So... why didn't you buy the 990 Pro with heatsink?
The Hiksemi heatsink may not fit, since on the MoBo, there is one microcontroller chip, which would be just below M.2 drive. Hiksemi heatsink has backplate and it may interfere with the microcontroller chip on the MoBo (e.g doesn't fit).
Money and performance wise, PCI-E 3.0 (Gen3) drive, e.g Samsung 970 Evo Plus, up to 2TB (since that's max what MoBo supports), would've been much better.
Some numbers;
990 Pro - max read: 7450 MB/s, max write: 6900 MB/s
PCI-E 3.0 - max bandwidth: 4000 MB/s
970 Evo Plus - max read: 3500 MB/s, max write: 3300 MB/s
So, if you go with 990 Pro, what you can get, is about half what the drive can actually deliver. But if you go with 970 Evo Plus, you can get full what drive is able to deliver.