Fosi Audio BT10A Bluetooth 5.0 Stereo Audio Amplifier Receiver 2 Channel Class D Mini Hi-Fi Integrated Amp for Home Passive Speakers 50W x 2 TPA3116

My outdoor music setup is some used Infinity marina/boat speakers, a Chromecast audio and a cheap stereo amp, withe the electronic bits in a cheap plastic Rubbermaid container. Something like this for the amp https://a.co/d/0ehIEqIW Something like this for speakers https://a.co/d/037WooJU Otherwise , just simplify and get a good Bluetooth speaker and bring it in when you are done.