Pixel 3 - No signs of life after battery replacement. What to check?

Hello! I just finished installing a new battery into my Pixel 3, but unfortunately am not seeing any signs of life. No vibrations, no screen activity (with/without charger), all while trying different button combos. The old battery wasn't really holding a charge very well but the phone did work. I've reconnected everything 3 times, nothing looks torn or damaged on the phone. The old battery did get its connector damaged during removal so I cannot test with that one.

What would y'all recommend I try next? How can I tell if the new battery is DOA?