Backblaze B2 Bucket Split Files

Rclone Backblaze B2 I How can I split my 6 TB bucket into 3 Existing Separate Accounts as 2TB?

hello and welcome to the forum,

the first step is to create a remote for each B2 account.

after that, need to figure out how to split the 6TiB into 3X2TiB.
as i have no idea of your setup, the mix of dir and files.
so cannot offer more than a generic suggestions.

--- can rclone move or rclone copy one or more directories from the source to each dest.
--- can use

rclone move source: dest01: --max-transfer=2T --dry-run
rclone move source: dest02: --max-transfer=2T --dry-run
rclone move source: dest03: --dry-run

in any case, would make sure the move is done server-side, not using local bandwidth.

use a rclone debug log, to see if the move is server-side or not.
INFO : file.ext: Copied (server-side copy)

might need to use --server-side-across-configs, might not need.
might need to adjust bucket permissions