Should I fix this iPhone?

So a customer bought a brand new iPhone SE around 6 months ago in our shop.

He came in with the problem that his battery was draining really fast. I also noticed the cable doesn’t plug in smoothly. Checked with 3utools and it said 93% battery health. I decided to take a look inside, because there is a crack on the glass strip on the back of the SE and I am almost sure Apple will not repair, because of it. To my surprise when I opened it I saw what looks like repair/refurbish traces. Solder spots on places where there should not be any, Flux on the sides of the CPU cover. Test points have little dents in them what should have left when probbing. Screw hole that has been stretched out a bit. Looks like a screw was forcibly screwed in.

The problem now is that the phone is restarting itself after a few min. I noticed a filter (FL2400) is missing which is right above the battery connector and I don’t know if it was already gone or I accidently removed it while removing the battery. It is charging with 0.2A, but that could be because of the “bad”battery. The phone also powers up with 1% charge and if I plug in the cable it goes up to whatever percentage it is on.

Battery info was also false, the health is at 81% and a 1:1 copy according to my battery tester. Checked the parts and everything is said to be original in 3utools. Dates are also correct when I type in the IMEI on the apple website. I have never seen an brand new iphone with traces like this. Should I take the loss and repair it myself or just send it to Apple and let them deal with it? This is the 2nd SE I have opened so I don’t know if it

I am ordering a new dock and battery to see if that helps the problem, but I doubt it will.