When beorg syncs a .org file it adds information about it to a database to help speed up various parts of beorg. Then when constructing the agenda it only looks at files with dated headlines. So any .org files which don't have dates attached to headlines (i.e. a planning line) should be ignored.
It isn't currently possible to ignore directories of files when constructing the agenda, only individually named files, but wouldn't be too hard to add. I wonder however if it is the sync process that is taking the time rather than constructing the agenda. You might find it worth checking the beorg debug log and see if you can determine which is taking the time. See https://www.beorg.app/support/debug/ for more details on viewing the log.
David Cao
Hello!
I saw in the init.org/library.org documentation that individual org files could be excluded from the agenda, but I was curious if this could be done for a whole directory of files.
I have a large collection of org files (~1.7k), and building the agenda with this many files is extremely slow; I'd like to move some of these files into subfolders such that they're still editable with Beorg, but aren't used for building the agenda, to speed this process up.