DOS policy allows K1 applicants to not be completely vaccinated at the time of the visa medical. If the applicant opts for such, the DS-3025 worksheet will be marked as "K visa applicant electing not to be vaccinated at medical examination". BUT, depending on the visa medical clinic, it could be very difficult to opt out, as the clinics are tasked by DOS to "make every effort to encourage K visa applicants to meet the vaccination requirements before admission to the United States".
You already quoted the relevant section from the DOS manual -- https://fam.state.gov/fam/09fam/09fam030202.html