Hello,

I just recently booked the flight from DUB-YYZ-YVR at end of May, all in one PNR via EI, upon close reading that I have to change terminal. Traveling myself and my partner.

DUB-YYZ with EI arriving to T3 at 16:05
YYZ-YVR with AC Departing from T1 at 18:00

Looking at connection guide on YYZ website

1. Leaving Aircraft, Head toward to immigration
2. after immigration, pick up bag from baggage carousels
3. Clear Custom
4. Drop off bag (Need advice here if I should drop off here and where to drop it or bring it to T1 and drop it off there)
5. Head over to T1 and clear security.
6. Head to D Gate for YVR flight.

So if all goes well and EI flight arrive on time then 1h 55m in YYZ, is this enough time to go through all the step.

This will be my first time in YYZ, any pointer to make life easier in this connection?

I did this DUB-YUL-YVR (All in AC) last year and it was smooth sailing with just immigration/custom only without having to pick my bag and having to go through security

Don't think there is an AC luggage counter at T3 (AC doesn't operate there) so best to bring it with you to recheck a T1.

Though it's out of fashion, using the ArriveCAN to fill out your customs details may help shave off a few seconds..

You are not arriving at T3 during "Rush hour" when there are multiple intl heavies arriving.
Your timing should be fine.
If your bags are tagged to your final destination, you can drop them off at T3 onward baggage for the system to send it over to T1 and AC.
You are allowed to personally take your bag to T1 and do your bags drop there as well.

During the present T3 luggage fiasco, I would take them over personally to make sure AC receives them.

You should be fine assuming everything is on time. Pickup your bag at T3 and bring it to the Air Canada counter at T1.
If you do miss your YYZ-YVR flight there are later flights.

T1 and T3 are connected by a train.