Will (partial) restoring destroy the fullbackup for further incremental backups?

our plan is to make a fullbackup with xtrabackup once, then create an incremental backup and merge (=apply) it with the full backup and repeat that every day. So that we have one backup directory that is updated with the incremental deltas every day. We would use “–apply-log-only” to make sure we could continue to create incremental backups.

Now, when we would need to restore some tables (or the whole backup), we must fully prepare it, i.e. without the --apply-log-only, did I get that right? If so, it would mean that even after only restoring a single table (using --export) the full backup could no longer be used for incremental backups and that we had to create a new full backup.

Is that right? To avoid tainting the full backup, could we just copy the the “main” files (ibdata1,xtrabackup_checkpoints etc.) and the tables we would like to restore to some other dir and perform the --prepare --export there? Or is that only possible on a complete copy of the full backup?