I have a few concerns.
1 - I don't know the Corsair power supplies very well, but I know some are good, some are bad, and some are good in certain years and bad in others, so I can't speak to the quality of the 2017 CX power supply. I'd recommend a Seasonic, and I generally would recommend a newer mode, but as keeping things within budget is a concern, I'd say go with this one - it's older, but has a little more margin for power, assuming you might want to add in a video card sometime in the next few years. But, a high-quality, reliable power supply is a must. Please note that high quality and bronze/gold/platinum/etc rating are not the same - the "color" rating is for efficiency, not for overall quality.
https://pcpartpicker.com/product/3G...-bronze-certified-atx-power-supply-ssr-550gb3
2 - The optical drive clashes with the case. Also, do you need an optical drive? If so, these days, I would probably recommend going with an external one that connects via USB.
3 - There are two issues with the RAM: a) a single stick runs in single-channel mode, hindering performance, and b) Ryzen likes faster RAM. There's a QVL list for RAM on the ASRock page for that motherboard, but it's a little tedious to go through the list looking for a matched pair of 4GB modules on PC Partpicker at the moment. I know the B450 boards aren't as fussy as the older boards when it comes to RAM, but my paranoid side still likes to stick to the QVL list.
4 - Do you necessarily need a full ATX motherboard? Are there several expansion cards you plan for in the future?
5 - Do you need wi-fi/wireless networking to be built-in to the board?
EDIT: other posters have addressed some of my concerns while I was typing...