Answer:
Affirmatively, ethnic groups seeking independence as free nations have other methods to achieve their goal, without incurring terrorist actions.
Although sadly we have plenty of examples of terrorist actions committed with the aim of forcing the independence of a certain ethnic group (ETA in favor of the independence of the Basque Country in Spain; or the terrorist actions of the Kurds in the Middle East), there are many other ethnicities who have sought their independence through peaceful means.
An example of this is Catalunia, which since 2012 has been trying to separate peacefully from Spain, even declaring its independence in 2017 after a popular referendum.
Another example of independence by peaceful means is that obtained by India, in which its population participated in non-violent protests and action measures against Great Britain, without incurring armed confrontations or sporadic attacks.
