You said this only occurs when syncing from a MyKinsta site. The sync itself uses rsync (over SSH). rsync itself is resumable, however the pull action I don’t believe is resumable if it fails. I do believe it uses zlib compression, although the compression is related to the SSH link, not the files.
I was able to successfully “pull” a site from my MyKinsta Company by going to DevKinsta Home, then clicking on Add Site → Custom Site → Import Backup
I filled in the Site name manually and it auto-populated the rest of the fields for it (though I manually ticked Enable HTTPS), then I selected a .zip file of a MyKinsta environment that I made using the Backups → Download (Downloadable Backups) method and had downloaded already.
Doing it this way, it doesn’t depend upon the rsync pull wrapper to deploy a site, and can be buffered from the local backup archive instead. You would just need to download the compressed downloadable backup first, and that download is resumable if your connection goes out for any reason.
Once you import the backup from your computer, and make the desired changes, you can then use the Sync menu in DevKinsta to push the changes for that DevKinsta Site to the desired MyKinsta environment from your computer.
Best regards,
Zach