It sounds to me like your wife's reaction was not actually about the tea.

If she described that as "too controlling", that likely indicates she perceives you as too controlling overall.

Regardless of the truth of her perceptions, they're all she has to go on in life, so it's her perceptions that matter, not the "objective truth" of whether you're controlling.

I don't know you or your wife at all - my analysis could be way off in a lot of ways.

Whatever the issue here is, though, it's not the tea itself. There is some negative perception or idea she has that you triggered when you helped make her tea. I strongly recommend you try to figure out what's beneath the surface there. It could be rooted in your behaviors, or it might go back to how other people in her life have treated her, or some combination. It could be that she's a flaming control freak who can't stand anyone doing anything that seems to her like a threat to her agency. I don't have enough context to have much of a clue.

Writing it off with "Okay, not gonna do that again" internally was a dangerous pattern for me - it led me to ignore issues for years instead of trying to deal with them head-on.

Warning: For me, dealing with these issues head-on was a painful, difficult road littered with ugly realizations about both myself and my spouse. Dealing with the pain and issues now beats waiting until they're worse down the road, though.

I found Marshall Rosenberg's Nonviolent Communication extremely helpful in learning to dig into what's under the surface of incidents like this one: https://en.wikipedia.org/wiki/Nonviolent_Communication

A nice person making tea for you is never a problem for anyone.

Its not just the tea. She's got needs that aren't being met. Best advice is to reflect back what she has said to try to understand what needs of hers aren't being met." Perhaps to your wife you could say the following 'Are you feeling angry because you have the need for more say in our relationship?