While I'm not part of XR myself and I'm not a super fan, I still invite you to stay in the group, especially if you lack alternatives. You have a lot to learn, especially because you disagree with what you perceive is the general strategy.

XR is a movement that locally employs a diversity of tactics and it's not a homogeneous, centrally-directed organization. So when you say that "XR is demonstration oriented", you should understand it as an emergent property of the current situation in which XR is in, or at least your local chapter. It's not like that everywhere, but especially it doesn't have to be. While movements have their own DNA that is hard to alter, XR is relatively open to a diversity of tactics. Being part of a movement means also to have the ability to shape and direct its actions.

Let's be more concrete: once you forge relationships in your local chapter and you gain trust, you can start proposing different kinds of actions and bring change in the org. Learning to do that is a lot of work and it's far from trivial, but better doing it in XR than in a stale ML org full of old tankies. If XR identity is too far away from your proposals, you can gather interest for a side-project done with a different public identity: just because you meet people in XR and do stuff with them doesn't mean you have to go public as XR. You can for example create a lobbying group on your local politicians that is easier to talk to than XR, and then bring XR positions into a city council, for example.

If you feel your local chapter has become a machine to pump out demos without a broader strategy, point that out. Ask what's the long-term strategy, what's the theory of change, how do they expect to make things happen. Ask them to point you to document in which they analyze that: if they have them, your questions will remind them that they should stick to the strategy, if they don't have them push the chapter to set up sessions in which they develop their local strategy.