Well but you don't need to notarize all builds, just those that went through internal QA

Split the build process so that you can click "version 1.2.3" and have it notarized (this is doable in Jenkins for example)

My limited experience notarizing a hello world react electron app took 10 to 15 minutes. Not that much but a large increase from the 1 minute build time before

In my (limited) experience, for non-GB-sized apps, the turnaround time is closer to five minutes.

Can you hand it off to be notarized and then end that job, and have a hook to pick up when that's done?