Help understanding .dtBase2 and .dtCloud files, and syncing across to new computer?

I have DevonThink 3.6.1 and macOS 11.2 on my MBP.

I have a new MBP, that I am trying to transfer my DevonThink database files across to.

On the original computer, in DevonThink, if I go to “Globals” there is a single “Inbox” listed. If I right click on that, and go to Database Properties, it gives a location under ~/Library/Application Support/DEVONthink 3/Inbox.dtBase2 (3.66 GB).

On the original computer, in DevonThink, if I go to Preferences, Sync, I do see two “Local Sync Stores” that I’ve setup:

Both of these point to locations on Google Drive. (I have the desktop sync application installed).

The first of these, points to a .dtCloud file that is 2.89 GB. There is a Local location listed, but nothing under Remote. (See screenshot above).

The second of these points to a different .dtCloud file that is 4.72 GB. There is a Local item listed, and a Remote item:

(Sorry, forum won’t let me paste a second image).

Can anybody explain how these .dtBase2 and dtCloud files interact? I’m mightily confused.

What’s the best way of syncing across all my files, so I don’t lose anything to the new Macbook? And then of getting the two syncs back in order?

Second screenshot:

Instead of using sync for this purpose, why don’t you just connect the old and new machines together (sharing, using standard Apple networking features) on the local network and then copy the DEVONthink databases from old folder to new folder? I’m assuming you have a local network available.

Check out the Help > Documentation > In & Out > Sync section. This covers the philosophy and processes with sync, addressing many questions about it all.