The title of section FAR 36.213 is Special Procedures for Sealed Bidding in Construction Contracting, so technically this section applies only when doing an IFB for construction.  Thus your reference of FAR 36.213-2(a) on issuing presolicitation notices does apply to IFBs for construction over the SAT. While it is not required at the SAT and below it is left to the contracting officer discretion.  This is not in conflict with FAR part 5 guidance.  This is an additional notice that goes out in advance of the synopsis. These notices shall be issued sufficiently in advance of the issue date of invitation for bid to stimulate the interest in the greatest number of prospective bidders.  This is normally accomplished 30 to 45 days prior to the issuance of the synopsis.

The purpose of this notice is to provide the contractors sufficient time to form their teams and initiate the preparation of their bids. This notice is often done via email or through the GPE.

As far as issuing a presolicitation notice for a RFP in construction, FAR part 36 does not speak to it directly, so it is not required.  However, it does not forbid it either.  At the contracting officer’s discretion, if the contracting officer believes issuing the presolicitation notice will be beneficial to competition then there is nothing precluding the contracting officer from also issuing a presolicitation notice for a RFP.