Retention always takes precedence over permanent deletion, with the longest retention period taking preference.
The delete action from a retention label always takes precedence over the delete action from a retention policy.
Reference:
https://docs.microsoft.com/en-us/microsoft-365/compliance/retention?view=o365-worldwide#the- principles-of-retention-or-what-takes-precedence

Use Preservation Lock to restrict changes to retention policies and retention label policies Important Currently, adaptive policy scopes don't support Preservation Lock.
Reference:
https://learn.microsoft.com/en-us/purview/retention-preservation-lock