If you have used the same USB cable, hub, and port to connect the encrypted APFS SSDs, NTFS drive, and HFS disk, but only the encrypted APFS SSDs are unmountable, then the problem should not be the connection.
Did you install the same version of macOS Ventura on the four Macs? OS malfunction is also a possible cause when the encrypted APFS SSDs became unmountable in Disk Utility. If so, try to reinstall macOS, update macOS, or downgrade macOS to fix the issue.
Besides, if you have encrypted the SSDs with APFS in a third-party application, then that could also be the culprit. macOS Ventura may not support the application, therefore you find the SSDs unmountable on Macs.
In addition, the APFS-encrypted SSDs that are unmountable could also be caused by virus/malware infection and file system corruption. Whatever the reason, you can try the following solutions when an external hard drive is not mounting on a Mac and first recover data from an unmountable drive with iBoysoft Data Recovery for Mac.
- Manually mount the drive by clicking the Mount button in Disk Utility.
- Run First Aid to repair the unmountable SSD.
- Format the external hard drive on Mac.
