Ten thousand years from now, will this argument still matter? Start there.

Distance changes the size of things. An argument that feels enormous right now is being measured against this week, and almost none of it survives a longer frame, which is worth knowing before you say something that will outlast the disagreement. This is not a claim that your feelings are unimportant, only that the scale you are using is short.

Ask whether this will matter in a year, and answer honestly, because sometimes the answer is yes. If it is no, let it go first and quickly. If it is yes, treat it seriously instead of fighting about it.