Sounds like you have similar needs as me. I got some good advice here for using a secondary APVTS attached to a dummy processor instance: How to safely attach UI components to non-automatable plugin state with undo history and persistence?
I’m the only one testing my plugin so far (it’s not released), and I often test with the standalone outside a DAW, so I don’t know if there could be issues with this approach, but it’s been working very well for me for the past 6 months. I plan to continue doing things this way for the foreseeable future.