Starting with VCF 5.2, VMware enforced a minimum 15-character password length for both Cloud-Builder (admin/root) & SDDC Manager (root/vcf). VMware enforced this change as part of STIG compliance for Photon OS. STIG compliance rule: ‘The Photon operating system must enforce a minimum 15-character password length.’
https://www.stigviewer.com/stig/vmware_vsphere_8.0_vcenter_appliance_photon_os_4.0/2023-10-29/finding/V-258823
Deploying Cloud-builder OVF detailing new password complexity requirements for Admin/Root passwords:
Credentials tab of the parameter sheet detailing new password complexity requirements for SDDC Manager: