Just do some research and get a cheap class D amp off a chinese website. I forgot the one I chose(I'm at work now), but other than some sparks if you jiggle the power connector(haha seriously. can be fixed with a tiny bit of effort), it is an amazing little amp. It also supports optical and bluetooth connections which is really nice.

I put my efforts into building speakers instead. I got a cheap kit (https://www.diysoundgroup.com/overnight-sensations.html) and spent my time learning how to apply a french polish finish. I really enjoyed learning french polishing. It's one of those things that when you finally get it, it becomes immensely satisfying. Yeah, shellac isn't the most durable finish, but it sure is pretty.