Are you limited to micro ATX because of the case model? Because if not, it seems silly to drastically reduce your options on a productivity machine with a mATX limitation.
From what's available right now, and it's not much because the Zen2 release and expense of X570 boards has crushed the availability of B450 motherboards, I don't see much reason to go with anything more expensive than this, which has all the connectivity and features you'd want including plenty of fan headers and four DIMM slots even though it's a micro ATX board, unless you have plans to overclock.
The Pro4 boards have always shone through as solid budget offerings. Anything more is going to be primarily focused on gaming features or overclocking. If you can use a full sized ATX board, there'd be a lot more options available in terms of board models, but even so, this would still be a good choice without a specific reason why something more is needed.
What is your case model, just so we can be sure your case supports the ATX form factor. You don't want to order a board that isn't going to fit your case.
Overclocking on Ryzen is a precarious notion. There really isn't much room for overclocking no matter what board you buy or what piece of silicon you get. Truthfully, if you want to overclock at all, I'd opt for the higher end X470 SLI master or maybe the B450 Gaming Pro carbon.
Bottom line is that if you want to overclock, you better plan on increasing that budget from 120 dollars to something closer to 175-200 dollars for a really decent board.