Entwickler is pretty common in Berlin, but I've not quantified it as a percentage as I'm definitely not close to C1 standard even now, and have always skipped such adverts in the past: https://www.stepstone.de/jobs/entwickler/in-berlin

And Berlin is (I'm told by everyone here) much more English language than anywhere else in Germany.

Depends on the company and jobs platform.

For conservative big names engineering like Bosch, Simenns or traditional mittlestand companies that mostly operate with German customers, yes they still use it. Xing is full of German only job ads.

But for software only companies operating international looking to attract foreign talent off LinkeIn, no, it's all English.

It's still used quite a lot.