If you hadn't already ordered the motherboard, I'd say wait a while if you're not comfortable with the process, but it would take time to get updated motherboards out. Otherwise, it isn't that big of deal, -if- you're comfortable swapping processors (me, takes maybe 5 minutes, they look basically like the last AMD I put together, I like Intel's setup better with the pins in the socket not on the processor, less likely to bend, not that it's likely to bend any though). It looks like you need to have both the motherboard and new processor in hand. ASRock themselves might help according to what I read, but if they don't, AMD sends out a chip to temporarily boot and update the bios, and then you send it back when done. Doesn't cost anything, I guess they don't ask for a credit card even. Newegg might exchange it for an updated one too. Bios update is described on the page, but don't get the one for Windows, get the other one, extract the file, copy to the base of a usb drive not in any folder, boot into the bios and update section.https://support.amd.com/en-us/kb-articles/Pages/2Gen-Ryzen-AM4-System-Bootup.aspx
Sorry about this, like I was thinking, they should have had a failsafe/compatibility mode, don't think it would have been difficult to figure out something to make it a bit easier. I didn't see it mentioned in the couple articles I read about the processors either. I know the process is annoying, but I'd think any of the companies involved are reputable, and will take care of you. The chip you chose does look very good, had it been out when I ordered, it would have been a consideration for sure.
Edit: Had this ~issue been going on, I would have ordered anyway.