Yes - changes made in a Template are automatically pushed to all Networks bound to that Template.
Bear this in mind, when organizing your Dashboard; where might you need to test a planned change, in a limited way, before you push that change to all sites...?
There are, however, a number of settings that cannot be locally overridden. It should become obvious to you what these are, by loooking at 'Configure' on a Network bound to a Template.
https://documentation.meraki.com/General_Administration/Templates_and_Config_Sync/Managing_Multiple_...
What do you need to change, per Network?
Remember there are essentially no limits to the number of Templates you can use. If something needs to be locally over-ridden for a subset of sites - maybe you need more than one Template?
If Templates are ultimately not flexible enough for you, that's where the Dashboard API comes in, for automating changes at scale.