Which branch is best to join as an officer having no military experience and 2 degrees?

The question really comes down to your personal interests. The Air Force and Navy lean more toward the technical areas. From what I've seen and officers I've known, the Air Force is rather stratified by being a pilot or not. The Navy is rather old school and the Officers and Enlisted personnel have strict lines of separation. It's just the way it is. The Coast Guard pretty much follows the Navy model.
The Army and Marines are more blurred in terms of Officer/Enlisted mingling (eating, living conditions, communication...). But, there are still lines not to cross there. The Army is a mix of technical, skill trades and just plain 'grunt work'. A good all around service, but I'm somewhat biased.
The Marines take a lot of hits from the other services, but they are hard chargers and since they are a smaller service, tend to be more stringent and lower rates when it comes to promotion. That doesn't mean it's easier in the other services, but with larger requirements come relatively higher rates of promotion.
As for knowledge to have, once you pick the service, start learning some of the base line knowledge such as rank structures, common terms, service creed and ethos. If you can get ahead on those, you'll have a little less stress as you learn other basic knowledge.
Recruiter wise, ask to speak with either the detachment XO or Commander, then work on your contract.

The vast majority of officers serve in military occupational specialties (MOS) that do not directly align with their college education. After you complete your commissioning program, you will attend some sort of officer basic course that will train you in your MOS. So the answer can only be determined by what you want from your military experience/career.

There are so many permutations that it is difficult to give you a meaningful answer. Any general answer will have some absolute exceptions completely contrary to the advice we might give.

You must prioritize:
Geographic stability
Travel
Post-military skill set/career
Service "corporate culture"
MOS "corporate culture"
Physical nature of the work
Intellectual nature of the work
Danger
etc. etc. etc.

No matter which service you join or job you choose, you can rest assured that every part of the military is geared to entry-level training, no experience required. No assumption is made that you know anything at all about basic hygiene, rules and regulations, or even how to speak english. Everything is geared around the lowest common denominator. I wouldn’t worry too much about your lack of any prior experience. You should focus more on which service and job feels like a fit for you. The military will take care of the rest.

Only you can answer that. Figure out what you want to do, what journey you want to make, and where you want to wind up. Then, research which branch will help you best achieve those goals.

What sort of degrees do you hold? The subjects of your academic degrees would have some influence on what military service or branch might suit you best.

Brittany B All the branches, including the Coast Guard, have something to offer. Research the opportunities that they each offer, and pick the one that seems to be the best fit. Good luck.

https://www.military.com/join-armed-forces/military-service-branches-compared.html

https://www.thebalancecareers.com/u-s-military [login to see]

For sheer quality of life - join the Air Force. Of course, the AF doesn't have jobs for everyone, so sacrifices may need to be made.

It’s difficult to say which is better. If I were you, I would select the branch that has the career field I want and go for it. Are you interested in flying? Are you interested in planning/project management? Engineering? Healthcare? Logistics? Do you want to go to special schools like Airborne, Ranger, etc. ? Research each branch to find your interest and go for it. You may not get what you want at first but as your career progresses you will have options to change career fields...at least in the Army.

I would say stay with education if you can. I would Look first at the ANG (Army National Guard) that would give a fair Idea if the Military is going to be something you like. Never kick out the Idea of Air force either. Speak with all the Recruiters and see who makes the best offer and if you can find a Current Officer to mentor you through and explain things your not sure about. JMT

That is a very subjective question. You will be hard pressed to find anyone on here who has served in several branches let alone in multiple branches as an officer. I was enlisted in the Air Force and found it boring. I enlisted in the Army and ultimately became an Army Officer. It really all depends on what you would like to do. As a National Guardsman if you go that route try to serve in a capacity that is the polar opposite of what you do in the civilian world. Good luck