I have a JBL Link Portable, which seems to be out of stock, but should fill most of your requirements if you can get your hands on one:

• supports Chromecast Audio, AirPlay, and BT
• sounds good
• has good battery (I get 7-8h of playtime against 8h quotes battery life)
• charges over USB-C (both via an included charging dock and a direct cable connection

The only downside is that it has Google’s voice assistant built in, but you can turn it off.

Dance Yrself Clean by LCD Soundsystem would be my choice.