My phone always got pretty warm during charging. And I assumed that is normal due to quick charging. But it isn't!
Also, I thought my phone’s socket itself was too loose inside the phone. That wasn’t true either!

The Blackview cable if far too loose, and creates lots of resistance. Hence the phone charges slower too and the battery may be harmed as well (e.g. due to heat).

I got a new cable from e-bay, and used a box cutter to slice off a bit of the rubber of its connector, so it would fit in.
Now my phone charges in 1 hour again instead of up to 8 hours, and plugging it in always works.
And it doesn’t get hot anymore! At most, one can barely feel it getting a biiit warmer.

So if you are having the same problems, just get a new cable. Even 2 meters is totally fine.
This is the one I bought: https://i.ebayimg.com/images/g/C68AAOSwQPlV9Tdr/s-l500.jpg