Reported today- macOS 28 will no longer support encrypted Mac OS Extended (HFS+) volumes. Where does this leave us for securing external drives that we want password protected???
If you want to keep the HFS+ file system, then...
1. Turn off encryption
2. If the drives have sensitive data on them, then lock them up when not in use.
I would -NEVER- encrypt a drive without an absolute reason to do so. I have only ONE encrypted partition (on a drive with 3 other non-encrypted partitions), which serves as my "off-site backup" which I keep in my car. The encrypted P has bank records, etc. -- stuff that needs to be protected...
You can also create encrypted disk images on the external disk (using the Disk Utility app), or use a third-party app like Veracrypt or Disk Decipher to create encrypted disk images on the external drive, if you need to access the drives on non-MacOS machines. Mounting disk images (especially when created from Disk Utility) isn't much different from accessing external drives in Finder.