No, I would say not.

I've had it for about 2 weeks, so far I haven't been able to tell...

In operation for months, even during the heatwave, never noticed anything like this.

I wouldn't say that now either.

Mine overheats at every opportunity. Even when charging slowly, you can barely hold the device in your hand after about 20 minutes. Video and charging is painful, gaming and charging impossible. Even without charging, it gets very warm on a soft surface.
It's probably not dangerous, but it certainly damages the otherwise good battery.
I very much regret having bought this phone.