Dead iPhone 15 Pro Max after charging overnight

I always charge my phone overnight on a wireless charger. Lastnight (10/5/2023) I did as well except this time I used a usb-c to usb-c cable instead of just laying it on the charging pad. This charging pad has the option to charge your phone with a cable, which is what I was going for. So I wake up to my alarm going off except it’s from my Apple Watch Series 4. I’m confused and look at my iPhone but it’s dead other than the fact it’s displaying that it can still be located via find my phone. I unplug it from mobile charger and plug it back in with same cable onto wall charger. A minute or so later I see it come to life with 1% charge. I looked at the battery usage history and it seems as if the portable charger did its job but soon after the battery on the phone started dropping dramatically. I went back to check on the portable charger but that too was dead. Was my iPhone attempting to charge my charger? Does this infer I can’t be using a portable charger on my iPhone overnight or else I might wake up to a dead phone again? Thanks for any input. Btw I am running the latest iOS patch (17.0.3).