I have a nice amp (Loxjie A30), but the bluetooth connection is both fidgety and subject to all the usual bluetooth incompetence (year 20 of the alpha test.)

I have a raspberry pi running a spotify connect implementation outputting audio to the amp via usb. It sits there and silently (or, well, not so silently) works; it's great!

There's some mucking with alsa to get it set up, but under 90 minutes.