First since this is an M1 laptop, make sure to set the "Allow accessories to connect as" in the Privacy & Security System Settings to "Always when unlocked". This avoids missing the pop-up notice asking for permission to allow the external device to connect. I don't feel this particular setting "Always when unlocked" lessens security at all since the laptop is being actively used at the time & you will just click "Allow" when seeing the pop-up notice anyway. When the screen is locked or the system is sleeping, then external devices won't be allowed until the laptop is unlocked.
What file system is on each of those external drives?
What is the exact model of your Mac and version of macOS being used? You can get this information by clicking the Apple menu and clicking "About This Mac".
Are these ADATA SSDs? If so, what enclosure, drive dock, adapter are you using with them? How long have you been using them?
What happened between the last time those drives mounted and when they did not mount?
Did the issue occur at the exact same time for both drives?
Are these drives always connected, or do you just connect them as needed?
Are these data only drives or drives for backups.....if the latter, what type of backups? Time Machine, third party app, or manual copy of data?
Do the physical drives appear in Disk Utility on the left pane? Within Disk Utility you may need to click "View" and select "Show All Devices" before the physical drives appear on the left pane of Disk Utility. We need to know if the physical drives are seen.....if they are not seen, then it means there is a hardware issue of some sort (external drive, cable, USB port, adapter, dock, hub, etc.). If the physical drive is seen, then it could still be a hardware issue, but it could also be due to file system issues on the drive.
Have you tried running Disk Utility First Aid on these drives? First run First Aid on the physical drive, then run it on the volume.......if using the APFS file system, then run it on the hidden Container. Even if the First Aid summary says everything is "Ok", click "Show Details" and scroll back through the report to see if any unfixed errors are listed. If there are errors, then run First Aid again until the errors are gone. If after several scans the errors remain, then it means they cannot be fixed.