You can't disable the only launcher on your phone. Just install another launcher, set that launcher as your default, and the end result is exactly what you would want (no Google launcher running). This is not possible at all on iOS.
Also, you've once again conflated "stock" with Google phone. If you use more precise terminology, you won't be so confused.
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.
I can’t even disable this Google bloatware on a stock phone (Nexus 5X)