No no no no no. You should never, EVER go into anything to please others, least of all your professors. You can talk to your program where you were admitted and ask for a deferral or simply decline. IT IS OK TO DECLINE AN OFFER. Trust me. A good professor will always be proud of you, no matter what you choose, so long it's your choice. And if anyone gets offended, well, it's their problem.
Before you accept or decline, please consider the resources at your disposal for performing a vigorous due diligence for each of your potential options. Please way the benefits and challenges (not pros and cons) of each option.
FWIW, The way I see it, you have at least five centered around attending graduate school
defer
accept with intent to push through to the doctorate with your intended fields
accept with the intent to reassess after earning a masters with your intended fields
accept with the intent to earn a master's degree while (covertly) developing skills for a job outside of history.
You could use the outside field requirement to develop a skill in data science or project management.
Just make sure that the skill isn't something with a very limited shelf life.
accept with the intent to earn a doctorate with fields that will help you get a job outside of the Ivory Tower.
As an example, if your top 10 school's name starts with a Y or a H or a P or a J, and your interests are anywhere adjacent to security studies/grand strategy you could put together a path of study that leads to a job with .GOV or .MIL
For options in the private sector, I recommend that viable alternatives should comparable favorably to what you'd be giving up by not going to graduate school. That is, you have an offer of "guaranteed" underemployment with health insurance and great amenities (like the library) during an interval of
intensifying great power rivalry,
economic uncertainty,
a pandemic that doesn't care if people think it should be classified as an endemic,
political turbulence.
Please also take a look at your theory that you're overthinking things. To what extent is "over thinking" a trait that that has kept you out of bad situations or a potential character flaw that has led you to walking away from opportunities for personal fulfilment and success. The latter can really become a grind if left unchecked. Or so I've heard.
Please do consider talking to your professors candidly about your ambivalence. Before initiating such a conversation, make sure that you're going to be able to speak frankly about your hopes, your fears, and your understanding of their expectations. (On this last point, I think that @AP will prove to be right. I think that your professors like you personally.)
