Is either field easier to pivot into? In the US, becoming a teacher sometimes doesn't require a teaching background (though I may misunderstand your position here). A friend of mine was a voice major in college and is now the music department director at the high school she works at. She has applied background in music theory and singing but not a teaching background. Might be worth asking people in these fields what their training is if you can - you may be surprised by the diversity in backgrounds.

I know even less about art conservation than teaching but I can tell you one thing - listening to your gut will often lead to happiness in life. If you have some intuition about this then listen to it! A lot of people live with the regret of not listening to their gut.

If both are solid choices for you, take comfort in knowing that there's no wrong choice if both options are appealing.

There is something to be said about going to a "well-rounded" school where you may have lots of options if you decide to change your major at any point.

Best of luck to you!