How do I deal with cost work no one notices until it spikes?

You keep the spend lean, and the reward for doing it well is that no one notices. Your discipline is invisible precisely because it works; the bill only becomes visible when someone lets it spike. That is a thankless shape of work, and the resentment makes sense. Prevention is always quiet. The person who stops the fire never gets the credit the firefighter does. But there is a way to make the invisible visible: show the spike that did not happen. Numbers no one felt can be named, and naming them is how quiet work earns its due. Each month, put one plain figure in front of your team, what the spend would have been without your work versus what it was. You are not bragging; you are translating prevention into something people can see. The discipline will always be quiet. It does not have to stay unspoken.