Is it possible to run plugins with jack when running ardour, for example say I have a lv2 or ladspa plugin I wanted to run with jack that affects all the audio from that connection so that when I use ardour that plugin is running in the background with all jack sessions when I run ardour?
You can run Plugins using a Jack Host. So depending on your OS, Carla for instance can act as a host and just run plugins, and provide ports to and from.
However automation becomes a bit trickier as now you are outside of Ardour for audio processing, and you would need to route the tracks two/from Carla or whatever host.
Some Open Source plugins especially also provide standalone versions of themselves that can be run as Jack Clients, this just removes the need for a plugin host.
If you go this route you might look into a studio manager software solution, it has been a LONG time since I looked at those though so I can’t give you much feedback on them.