If I’m often passing out, would the military consider Med boarding me if they do or don’t find a cause?

The process of the Med Board will be initiated by your medical provider, depending on what they find. The only person that will tell you yay or nay for Med Board is your doctor. Talk with them. Anything said outside of that would be pure speculation.

What you have is typically called Syncope and it is typically classified as four types. See Clev Clinic site link. After 31 years in the Army Reserve, during my 2016 - 17 deployment, I went through a series of Syncope events, along with migraine headaches / panic attacks. I was redeployed from Kuwait and sent from Fort Hood to Fort Campbell WWC for a few months until I 'retired'. I still work but my Army Reserve 'retirement' will kick in a few more years at 58.

I can't tell you how demoralizing it was for me to go from always ready to not knowing when I was going to have an event that would put me in the Intensive Care. It was not how I wanted my career to end, but, it is what happened.

Ultimately I had a enlarged aortic root stem that would caused this problem, also had genes associated with this condition for all my kids to check and a family history of sudden cardiac death for Uncles and a Grandpa that I was not aware of until these events occurred.

If you are on active duty they will medically work to figure it out, don't leave active duty without knowing the likely cause and what treatments you will need.

https://my.clevelandclinic.org/health/diseases/17536-syncope

Right now just focus on getting the tests and diagnosis done. They won't refer anything until they can identify the cause and potential solutions. But once they sort everything out it is possible this may be sent to a med board but you are extremely early in the process. Just focus on now and worry about next week when you get there.