My experience with the PSU:
July 30th 2023 application for a proof of citizenship for my child born abroad (father is Canadian). Since I only had the birth certificate for my child I sent a letter explaining that I only had one piece of ID for the baby.
After sending the request for the proof of citizenship I immediately applied at the nearest consulate for a Canadian passport for the child. A trip to Canada was planned for early January which justified the need for a temporary passport while waiting for the proof of citizenship. Passport received by mail 3 weeks later.
December 18 2023, case sent to the PSU because of missing documents (only one ID).
March 22 2024 I received an email from the PSU agent requesting the second ID. Acceptable forms of ID included a passport, immunization record or medical service card. I sent the baby's new Canadian passport as well as immunization record.
March 23 2024, request for proof of citizenship approved and proof delivered via the portal.
Total wait time roughly 33 weeks.
Overall I was really happy the agent contacted me by mail which seems to have accelerated the process. Also, for those with children born abroad applying for a temporary passport was brilliant. We had no issues at the Canadian border and it allowed us to visit family while waiting.
Good luck everyone.