Possible IC chip damage?

Some days ago I put my iPhone SE to charge overnight with a MFi certified cable and a random usb wall plug, as I didn’t have the original charger around that day, but I thought having a genuine cable was enough to prevent possible damage to the device.

The iPhone had still a good percentage of battery left when I put it to charge at night, but the next morning it was completely dead, while still connected to the charger. No power up, no low battery indicator, doesn’t get recognized by iTunes.

The cable and usb charger aren’t damaged and still work with another device. I’ve opened the SE and did some tests with a multimeter, and here’s what I got so far:

• No obvious signs of damage inside the case, neither inside the lightning port
• The battery voltage is 3.4V; I replaced it two months ago with an iFixit battery so it’s highly unlikely that could be the problem. Anyways I disconnected it and connected the old original battery (which probably no charge, but had a voltage of 3V) but no signs of improvement
• With the phone connected under charge, the multimeter reads 0V from the pins inside the battery connector socket

All this makes me think the Tristarchip is damaged and so there’s nothing worth doing to the phone, as sending it to repair this kind of problem would probably cost more than another used iPhone SE now. However I still want to exclude any other possible culprit; for example could the cause be the lightning dock instead?

I’d like to know if in your opinion is the port or anything else worth checking or replacing, before spending 30$ for a new port that might be better invested in buying a new phone; or if these symptoms indicate almost certain chip failure.

To clarify, I’m no expert in iPhone internal electronics besides having done some basic replacements, and know about the tristar stuff from reading about it in the past days.

Thanks in advance!