Element is exactly what I've been looking for. A host that I can use to combine and play plug-ins (VST, VST3 or AU) and optionally live sound, for playing live and experimenting without the overhead of a full-blown DAW.
I've used Audiobus on iOS and was using Minihost Modular from Image Line on macOS. Minihost Modular is 64-bit, but is getting long in the tooth; a number of plug-ins no longer load or work properly for me, and it seems to have been abandoned (last updated 2014).
Element looks like a great replacement for me. It has a number of nice features, including over 25 plug-ins that come within the package. Like Audiobus and Minihost Modular, it lets me wire together plug-ins and save sessions that preserve plug-in settings, preset choices, etc. for the next time I open them; almost like building custom instruments for live play.
I'm still learning to use the application, and there are some workflow and interface challenges, but so far I have been able to use it for live playing and have mapped a MIDI controller to the Element-supplied Wet/Dry control for dynamic control of effects.
I'm quite happy with it so far and will be investing more time in using it and providing feedback to the developers. I'm giving this a 4 star for now, as I haven't explored all features (or using it as a plug-in in a DAW), I've run into a few minor glitches and the workflow and user interface are a bit awkward at times. Also, the current 0.46.3 release (including the latest tag on GitHub) dates back to July 2021. There is some recent activity in GitHub, so I hope there will be a new release soon.
It takes a bit of getting used to setting it up and using it, but it's well worth the effort. It does exactly what I wanted; provides a flexible virtual controller that turns my MacBook's trackpad into an X/Y pad, a set of sliders, or a trigger pad that can be customized and configured to work with my DAW or other MIDI apps. I haven't explored using it as a mixer control yet. I like the use of the MacBook Touchbar for quick access to switching modes and transport controls; one of the few apps that justify using the Touchbar, in my experience.
Give it a try - there is a free trial demo which provides a full version of AudioSwift that can be used for 15 days.