In the Lightroom export dialogue box for LRTimelapse, where it says "Intermediate File Format", 4K is the designated intermediate size. Without any option to change that resolution, it seems counterintuitive to me to then render 5k or 6k footage out of LRT Pro from 4k jpegs.

My question is, can this be changed so that I can render out these intermediate jpegs at 5k? If not, why? Thanks for any insight that can be offered.

Currently this is not possible. If you want to use 5K or 6K use the TIFF export, it will create the intermediates in 6K.
Will see if I can add more options in upcoming versions.

Thanks for the information, Gunther. Would love to see that option built-in with future versions. Will try the other route for now.