How to force a plugin to sample original clip resolution?

I work a lot with mixed resolution footage for 1080p or 4k delivery. The trouble I'm having in Resolve is with reframed 5.7k 360 footage, which I'm attempting to deliver in a 1080p flat video format. The reframe plugin I found for 360 footage (Karta VR) samples the 360 clips after they've been downscaled to the timeline resolution (1080p or 4k), so basically I'm getting the image quality as if I'd zoomed into a 1080p clip by 300-400%. Needless to say that yields a pretty unusable result. The only workaround I've been able to figure out is to change my entire timeline and output resolution to 5.7k or better, at the cost of huge file sizes and very long renders.

Is there a way that I can force plugins to sample my original 5.7k footage when it's dropped into a 1080p timeline?

Thanks

The Fusion page processes the footage at the original resolution.
Have you tried applying the effect there?

I did try applying it at the fusion page and it doesn't seem to make a difference. It's also harder to animate the reframing in fusion because you can't see the clip in the context of the rest of the timeline.