https://gitlab.freedesktop.org/pulseaudio/pulseaudio/-/tree/master/shell-completion contains bash and zsh completions. Please include these and symlink all relevant commands (e.g. pactl, etc.)

As an example, a (now deleted) package did this:

aliases=(
'pacat'
'pacmd'
'pactl'
'padsp'
'paplay'
'parec'
'parecord'
'pasuspender'
)
compdir="$pkgdir"/usr/share/bash-completion/completions
install -Dm 644 "$srcdir"/pulseaudio/shell-completion/bash/pulseaudio "$compdir"/pulseaudio
mkdir -p "$compdir"
for a in "${aliases[@]}"; do
ln -s pulseaudio "$compdir"/$a
done