With Myrlyn (or zypper), you always will have the option to review what is going to change in the system before committing it. When using a rolling release (in general), it’s always best not to just click through, but to look and understand.
Because the G07 driver and the G06 driver are for different hardware, the G07 driver isn’t considered an “upgrade”. It’s a distinctly separate driver, and it’s not going to get pulled in automatically (or replace an existing driver) unless someone’s made a mistake in defining dependencies.
For tumbleweed, using either Myrlyn or the CLI tool zypper dup is the way to handle upgrades. With the TW rolling release, each ‘update’ is actually an ‘upgrade’, and dup is what you use for upgrades. Myrlyn detects what it is running on and acts accordingly (and it uses the libzypp library that zypper uses, so all other functionality for doing upgrades should be identical).
Discover and PackageKit are things I generally disable.
For changing the runlevel, you’ll be using systemctl isolate <system-unit> - so for the multi-user target, for example, it would be systemctl isolate multi-user.target. (That would be the equivalent of init 3)