The disk Macintosh HD can't be unlocked

I am getting "the disk Macintosh HD can't be unlocked" popup error after reinstalling Catalina.

I checked Disk Utility, there are 3 partitions named, "Macintosh HD", "Macintosh HD - Data", "Macintosh HD - Data Data".

How can I fix this?

If you can still boot into the Recovery or Internet Recovery please open the Terminal app from the Utilities folder and copy the result of

du -f

and

diskutil apfs list

It is likely there was an issue with the install/migration and depending of free space you might have to erase and reinstall the OS (for that please follow the Apple guide at https://support.apple.com/guide/mac-help/reinstall-macos-mchlp1599/mac)

Editing the name of the drives so they are unique will help you know which is which.

This same thing happened to me. I had:

Macintosh HD

Macintosh HD - Data

Macintosh HD - Data - Data

One thing that has changed that I didn't know with Catalina is that when you look at Disk Utility it shows

Internal

Macintosh HD

That version (Macintosh HD) was greyed out for me. I couldn't First-Aid it, delete it, mount it, nothing.

I found that if you go to:

View > Show All Devices

It will show you

APPLE SSD <some serial number>
     Container disk2
           Macintosh HD

If you select that top node, (APPLE SSD), and then click erase and put in:

Name: Macintosh HD
Format: APFS or Mac OS Extended (Journaled)
Scheme: GUID Partition Table

Then it should ask for your AppleID Password and then it will delete the volume

Then you can proceed with the reinstall like you normally would.