why is my Macintosh HD locked?

EvaQueza wrote:

I have 2 Macintosh HD because one is locked. Im afraid its using too much space and I want to unlock or delete the first one. Also this is stopping me from upgrading to MacOS Ventura.

?

"upgrading to Ventura" from what... you do not say.

Since macOS Catalina and going forward—there a read-only system volume in macOS...

About the read-only system volume in macOS Catalina or later - Apple Support

since macOS Big Sur uses a “snapshot” of the current system for its (SSV) Signed System Volume, as you see in the list.

This is the new normal as well. This would be the 'Macintosh HD'

The macOS boots off the locked snapshot—

if you think you have an issue —

Let see the output from the Terminal.app copy and paste:

diskutil list internal

here is an example of what I see:

MacBook-Pro ~ % diskutil list internal

/dev/disk0 (internal, physical):

#: TYPE NAME SIZE IDENTIFIER

0: GUID_partition_scheme *1.0 TB disk0

1: EFI EFI 314.6 MB disk0s1

2: Apple_APFS Container disk1 1.0 TB disk0s2

/dev/disk1 (synthesized):

#: TYPE NAME SIZE IDENTIFIER

0: APFS Container Scheme - +1.0 TB disk1

Physical Store disk0s2

1: APFS Volume Macintosh HD 9.2 GB disk1s1

2: APFS Snapshot com.apple.os.update-... 9.2 GB disk1s1s1

3: APFS Volume Macintosh HD - Data 394.1 GB disk1s2

4: APFS Volume Preboot 2.0 GB disk1s3

5: APFS Volume Recovery 1.2 GB disk1s4

6: APFS Volume VM 4.3 GB disk1s5

MacBook-Pro ~ %