"Rugged" phones from OEMs such as DOOGEE are often sold via platforms such as AliExpress. However, this company has now announced that it is also now selling its S59 Pro on Amazon (in the US and the UK). This IP68/IP69K/MIL-STD-810G device has one of the largest batteries on the Android market, which powers on-board speakers rated for up to 2W of audio power.
https://www.notebookcheck.net/The-10-00mAh-battery-toting-DOOGEE-S59-Pro-is-now-available-on-Amazon.528832.0.html