While global military spending is only about 5.5% of total carbon emissions, it's all connected. Climate change impacts make wars more likely. Oil companies ally with fascists. Christian nationalists support Israel's war crimes; why Biden does is sadly less clear (as it will cost him votes). Fascist petro-states start wars.
The most important thing is system change, not individual consumer choices. Integrity helps, but just as we can't individually stop the war in Gaza, we can't individually stop the continued expansion of the fossil fuel industry. Many of us have little choice but to drive, or heat our homes with fossil fuels.
But if we change the politics, we can make an impact on all of these things.