Thanks for the additional details. I also have the Topaz app and I understand what you're looking to do.
First, though, think about workflow. In my opinion, it make more sense to put together the full video,export it via SVRT and
then run it through the upscaler.
It's possible that your souce clips (the original tape transfers) are SVRT-compatible, so try putting one of those clips on the timeline by itself and see if the SVRT track is active. If that works, then you'd be able to do all the editing on your source clips then feed the finished version to Topaz for upscaling.
Also, you can often create an SVRT-compatible output profile from the Profile Analyzer on the Produce page. Run the tool and see if anything viable comes up in the Intelligent SVRT panel.
I tried that with an MP4 clip made with the Artemis MP4 profile in the Video Enhance AI app, and I was able to have PD create an SVRT profile:
If that works for you, you're free to do everything in PD first then SVRT and upscale; or upscale all the individual clips then import them into PD and SVRT the final result