Clarification on which variables cause jitter when using lots of plugins.

I have a podcast project with 3 tracks, 2 x studio vox and one zoom feed.

On each of these tracks I use:

2 stages of Izotope noise reduction. 1 for continuous envirnmental noise (cicadas) and 1 for random noise (traffic etc)

2 x Fabfilter parametric EQs (1 pre compression & 1 post compression)

1 x Fabfilter compressor

1x Fabfilter limiter

Running this on a Macbook Pro i9 with 16gb ram.

Antelope Zentour interface for editing.96khz, 32bit float. Buffer at 4096

Recorded on a Zoom F6 at 96 to improve noise reduction outcomes and 32 bit for low noise floor.

Obviously, the noise reduction wouldn't be required in a perfect world, but we must deal with what we have for the moment.

With all of these effects chains on (not pre-rendered), I am experiencing severe jitter, preventing me from continuing to make adjustments. I have to turn off the effect racks on the tracks I am not using. This makes if difficult to make relative adjustments between tracks.

Buffer size is maxed out 4096, cpu load is only at 200% (1/4 load on 8 core processor) and RAM has tons to spare.

If my system reasources all have plenty of headroom and my buffer size is maxed out, what other factors are contributing to this issue?

I find prerendering doesn't allow me to make adjustments as I go, as the chain needs to re-prerender evertime I tweak.

I'm guessing I'm missing some fundamental knowledge on either the limitations of my system or possible adjustments to another variable.

I hope this all makes sense. I'm fully prepared to discover this will uncover a pretty massive hole in my knowledge. Momentary emabarrisment for long term gains...