Hi Eric,
It's never too late to get started. :)
I had the Allo USBridge Signature with me one year ago at our January, 2020 event (seems like ages ago, honestly). Link to the recording here.
There are a number of software solutions that support Raspberry Pi transports. In my experience, the best ones enable a division of labor which places the heavy processing work on a more powerful desktop PC. This work includes managing your local music library, responding to remote control apps, managing zone settings and what's playing where, uncompressing FLAC and other compressed formats to raw audio samples, etc.
With this division of labor, the low-power Raspberry Pi only has to copy digital audio from the network to the directly attached DAC. This helps to ensure reliable playback and to avoid processing noise from a busy CPU from adding noise to the DAC.
I'm happy to jump on a Zoom call with you if you'd like to discuss further.
-- David