Yeah, it's important to understand that as an officer in the regular Army, you do not have an ETS date. Your commission is indefinite and must be resigned. If you do nothing, then nothing happens because there is no expectation from HRC or S1 that you will necessarily separate at the end of your contract(s). Also, as scary as this, they are not obligated to accept your resignation, although the risk of that occurring is infinitesimal under current conditions.
FWIW, my S1 told me to expect REFRAD to take 7 months. I think that's an overestimation designed to keep people from waiting too long, but it speaks to the need to get things started well in advance.