With your need to preclear US immigration/customs should you leave airside, you will lose another hour, so leaving the airport is not really a practical option. In fact, your bags will be tagged through to the US, so you will actually be directed to a different routing whereby your bags will not even be inspected by Canadian customs but go right to US preclearance. Your passport will only be looked at in a cursory process by Canadian immigration too as a transit passenger from international to transborder. You'll be channeled right to an airside US preclearance area for connecting passengers.

While you can opt to go airside and through the normal Canadian inspection, if your bags are tagged to PHL, you will not be able to collect them at this inspection point as they will go automatically to this fast-track US transit routing.

So best to stay airside and consider other diversions.