charging, but won't charge & random reboots after light. port replacem

EDIT: https://pastebin.com/VQu0YieW -- system log while plugged in for few secs

Hello guys.

Right to the story - I have an iPhone SE 64gb for 18 months. Everything was 100% perfect, until 2 days ago.

2 days ago I wanted to take out threads & trash stuff from the lighting port, while I somehow accidentally scratched the lighting port, so it wouldn't charge anymore.

The iPhone had warranty for 1y, so I couldn't take it to iStores, as I didn't want to wait who-knows-how-long without my phone, so a friend came and took the iPhone, to replace the lighting port (with a original one, not some fake china spare part) ( he is doing these stuff for like 2 years now, has even it's own unofficial 'iPhone fix' store where he does this sort of thing all day ).

After few hours he returned, I gave him some money and few minutes later I've noticed my iPhone is a lil bit less smooth. I went with ignoring that fact, but then I've noticed my battery is crazy, I've had 42% battery, few seconds later it jumped to 28%, then a minute later I had 18%, 32% afterwards and more 'random' numbers. ATM I went from normal to paranoid mode, I've came home and took of the display to look up, if he didn't change the battery for a old one and maybe old CPU, etc, but I've found literally nothing, everything was original & not touched.

I've got these diagnostic data through my mac, but it doesn't say too much to me. Jun 29 17:10:48 iPhone UserEventAgent(ADEventListenerPlugin)[22] <Notice>: Unable to look up battery voltage Jun 29 17:10:49 iPhone UserEventAgent(ThermalMonitor)[22] <Notice>: <Error> batteryData NULL

I've called him, described everything and he told me, that I should try discharge the battery totally and then 100% charge it, to see if it helps. He also told me between that, that when he was fixing it, it didn't want to turn on, until he plugged in charger.

After that, I've been using the phone to discharge it ASAP, and then I've noticed it reboots randomly, too often.. My next steps were like this: Discharge to like 2% -> Restored backup from morning -> airplane mode -> plugged in charger After 2 hours I've looked and it got literally stuck on 20%, one hour later also 20%. I've let it in charger through the night, in the morning I had 13% with charging status. The rebooting randomly (and often) is very annoying also.

If anyone could help me, or had ANY idea, it would be super awesome.