I see that you’re conflicted and are looking for some POVs on this, etc., but the question may be phrased a bit too broadly. “War” would be conventionally defined as armed conflict involving at least one, but usually more, sovereign states. I would say that fighting for a state is misguided almost always, because you’re fighting for something that is inherently oppressive.
If you want to fight for an ideal that your state represents, maybe instead of going abroad and exporting it or “protecting” it, which is let’s face it a bunch of bullshit, look within and see how you can improve situations for people within your borders, the people who are marginalised, the people with limited opportunities, the people who the state ignores or actively excludes etc. Look into personal action, what you can do as an individual, and also ways of improving systems and institutions.
Now, if we’re talking about non-state actors, i.e. civil wars, insurgency etc. etc. then it’s a whole other thing. Are we talking about a repressive, authoritarian regime vs indigenous insurgency? I could see the argument for the latter but then it is theoretical, I have never participated in any conflict and as much as I believe in certain ideas, would I myself participate in armed resistance to protect them? Hell no, I’m just some dude, some academic who enjoys the comforts of his life. As a Russian person living in Europe, I wrote [EDIT: CW violence/torture] about my feelings on Euromaidan and what I could do on the outside to help, for instance, when it was kicking off, but like I said I did not end up going there, of course.
In the end each of us has their own lines, like @shivoa said, reality is messy. Whatever label you want to use to describe yourself, we each have a different interpretation of its meaning. Did supporting Euromaidan mean that I had to be present physically or otherwise I am not true to my beliefs? Of course not. Is being a Pacifist, in turn, mean that I have to be anti-violence or anti-conflict in general (note that I didn’t say anti-War) under any circumstances? Or is it about understanding the effects, meanings and uses of violence, striving to limit it but not necessarily vowing to never support it under any circumstances? I don’t know, its for you to decide. @shivoa is absolutely on point with regards to resisting other forms of violence outside of the context of “War” as well.
It is OK to be a hypocrite. It is OK to question your beliefs, and it is OK to not constantly act on them. Every single one of us is a hypocrite in one way or another, otherwise human beings would not be able to operate, like at all. For instance, I think climate change is bad, but I still use plastic products, I have a smartphone, I eat beef and I don’t always recycle everything. As long as we are aware of our various hypocrisies and think through them, like you seem to be doing (not to call you a hypocrite but just making the point that you’re working through your own beliefs now), then we are striving to be better. That’s a start.