Bridge is deprecated. JACK is the Linux-native means of doing what you are trying to do here.
Ardour and Non-Mixer actually use JACK ports natively when using JACK instead of ALSA. You can confirm in patchage (or newer QJackCtl’s graph viewer) that any routing you have done in Ardour, is actually being carried out by JACK. If you want to mix VST effects with Rack signals in Ardour you would insert a send/recieve in the Ardour mixer.