Does the resubmission rule apply to PF and DN only? Does it apply to a PI or an organisation or a topic of application?

For DN it applies to the proposal as a whole.

For PF, as of 2022, proposals involving the same beneficiary and individual researcher submitted to the previous call of MSCA Postdoctoral Fellowships under Horizon Europe and having received a score of less than 70% must not be resubmitted the following year.