I use a Plex server and the PlexAmp app wherever I want to listen. There are probably better options, but it’s something I set up years ago which was dead simple and requires almost no maintenance.

https://play.google.com/store/apps/details?id=com.rocketsauce83.musicsearch

ChordAI is an app that tries to figure out the guitar chords for songs found on YouTube. It also has a lyrics function, which can generate the lyrics from the song.

There is probably an app more specialized for karaoke, but this was the first one that sprang to my mind.