In writing an audio application for Linux, you can target either ALSA or JACK. PulseAudio and PipeWire present an ALSA device to applications, and PW presents a JACK device as well.

The choice of audio server really depends on your use case. The OP's application doesn't require any of the features of PulseAudio or PipeWire. ALSA alone would be sufficient. JACK provides the stability and predictable latency needed for professional music production while allowing easy patching among multiple applications. PA and PW are convenient for running multiple independent applications such as browsers and media players where central controls for volume, muting, etc. are desirable. PW does support JACK, but still lacks support for latency compensation among multiple signal paths that Ardour (a free, pro-quality DAW) provides.