Difference in operation Metadata store and Metadata actualize

Hey dear community,

I have a question of the above ( difference between metadata actualize and metadata store), because I a executing both operation. Metadata store has taken ( 2h ) while Metadata actualize is taken already 10h.

I am working on a MACPro with Monterey and archive is on an external harddisk connected via USB3. LrC is vers 13.01

For would be perfect to get explaination of differences of operations, because have not found those till now.

Thxs in advance for a helping hand

Br FJ