I have a different launcher installed, and in use. I backported the changes Google did in their launcher to Launcher3, built that, installed it, and am using it.
And by installing a different launcher, the Google apps never run, which is the effect you wanted to achieve. You gain nothing by disabling the apps after that.
If you were able to disable the apps and then uninstall the the new launcher, your phone would be unusable until you did a factory reset from recovery.
Incorrect. The Google apps are still used and running, e.g. for hotword detection even when the launcher is changed. And even with hotword detection off.
Not on the Pixel. On my Pixel, I can disable the Google app and if I use a different launcher, the Pixel launcher won't run at all. So they're getting more customizable over time.
Yet I can still not disable these Google apps.
EDIT: Screenshot https://i.k8r.eu/4ZLdMA