PHL TRACON Controller reported that the TEB RNAV (GPS) Y 19 has a transition area where ATC is not able to provide separation due to design resulting in critical airborne conflicts. Controller stated this has been a chronic confliction point by IAP design that has gone uncorrected.

Narrative

Aircraft X cleared for the RNAV Y 19 at 2000 and switched to TEB tower at about an 8 mile final. Teterboro tower shouted on the landline Approach; watch out for that 2000 VFR target. There was a 1200 code slightly northwest of the Teterboro Class Delta at 2000 and underneath the Bravo crossing the Runway 19 final on a collision course with Aircraft X. Neither aircraft were on my frequency; although I reached out to Aircraft X and the VFR to verify neither were on my frequency. The VFR appeared to take evasive action and climb while Aircraft X descended. I am BEGGING; absolutely BEGGING someone; an organization; any entity that cares about safety to review how dangerous the RNAV Y 19 is; as there is NO protection for IFR aircraft along the final approach course between UNVIL and TUGGZ. At minimum there should be a cutout AND/OR VFR traffic required to call Teterboro Tower for advisories. Controllers have been screaming about this for years. Please; PLEASE fix this. Teterboro on some occasions is busier than Newark. We as controllers should not be scrambling to separate a jet; or any large aircraft from a 1200 code in a critical phase of flight.