I get the Bluetooth units from Amazon. They come with the amp and the Bluetooth receiver in one unit.

These are my preferred model, but they are low wattage (15w per channel)

https://www.amazon.com/gp/product/B07TKN3GJM/ref=ppx_yo_dt_b_asin_title_o03_s00?ie=UTF8&psc=1

These are what I use if someone wants more wattage, but they have a shitty push button power switch that you have to account for when you do your build.

https://www.amazon.com/gp/product/B08R85MLZ1/ref=ppx_yo_dt_b_asin_title_o04_s00?ie=UTF8&psc=1

Hope that helps.