the 3B+ will do fine on performance. One concern is that the USB bus is shared with the network port. This might cause interference with the audio.
Other option is to look for a Odroid board, as these are also supported by volumio. The only downside with them is a different GPIO lay-out. So depending on your requirements for GPIO it might be a issue.
I am running Volumio on a Odriod N2+ which is running smoothly.
Or if you are OK with a x86 machine…