also also read some other topics about this issue, but i just can´t help myself

i want to realize following backups
VM 1: Sunday -- Full
Monday - Saturday -- incremental
Sunday -- Full 2
After Full 2 is created, i want him to delete the complete chain of Full 1 (VKB + VIB).
I set Delete VMs data retention by default: 14
I set Keep Restore points: 1
Last Sunday he didn´t delete the last chain, so i have 2 VKB files, which causes Dataspace problems.
Why Synthetic fulls didn´t delete?
Maybe the Delete Retention policy? What exactly is the function of this point?
Regards!