NEC now recommends whole house surge suppressionErik, I think you meant to say NEC now requires
Your State, county, or city, may not have adopted the 2020 NEC as yet. Check your State.
For new residential construction.
N = New for 2020 NEC.
N 230.67 Surge Protection.
N (A) Surge-Protective Device. All services supplying dwelling units shall be provided with a surge-protective device (SPD).
N (B) Location. The SPD shall be an integral part of the service equipment or shall be located immediately adjacent thereto.
Exception: The SPD shall not be required to be located in the service equipment as required in (B) if located at each next level distribution equipment downstream toward the load.
N (C) Type. The SPD shall be a Type 1 or Type 2 SPD.
N (D) Replacement. Where service equipment is replaced, all of the requirements of this section shall apply.
Note (D) Replacement.
"Exception: The SPD shall not be required to be located in the service equipment as required in (B) if located at each next level distribution equipment downstream toward the load."
The exception allows the SPD to be installed at the first Sub Panel (s) after the service equipment main disconnect(s), main breaker(s).
Never buy an SPD that is not UL Listed 1449-3rd Edition.
Why type 2 SPD must be mounted as close as possible to the electrical panel bus.