Invert Planar Transform too much for Fusion Studio?

Yes, I know, there are already infinity billion posts about this already but look at this screenshot and tell me what seems wrong to you:

3.1 FPS Fully Rendered.jpg (191.12 KiB) Viewed 3755 times

Granted I'm on a 2017 iMac Retina but it doesn't have these issues elsewhere. I've got 64 GBs of RAM and two Samsung 980 Pro 2TB NVMEs housed in Thunderbolt 3 enclosures — with a freshly installed OS and apps on one drive and caching on the other. I've double- and triple-checked my settings, using a 3:1 proxy, and I sat there for five minutes watching that green bar fill all the way up. And yet 3 fps is the best I can get. Is using planar tracker steady and then again to invert steady tracker asking too much? The fusion page in Resolve doesn't struggle nearly as much with this same node tree doubled and connect with Channel Booleans, but Resolve crashes on me frequently (another issue entirely).

To be clear, when I play back the Loader node, the first Planar Tracker node, or the Matte Control node I get full speed playback even without it having cached to memory, but if I play back the second Planar Transform or the Saver node, 3.1 fps is what I get.

What kind of video file are you dealing with?
What GPU are you using?

Radeon Pro 570 4GB and its a 4k VFX Connect from Resolve, 4k .mov, Apple ProRes 4444.

Apologies, check my edit above, I should have mentioned that it only does this when I play back the second Planar Tracker node (which is to invert steady transform) or the Saver node. Clean playback in all upstream nodes.

why not use a planar transform node instead. you can create it automatically from the first planar tracker.

I'm using this in resolve lately and not really having performance issues. even with 6K footage