Hello,
.
We are traveling home to USA from Prague. Tested positive day before original departure date and now are planning on using letter of recovery to get home in case we still test positive.

The issue is that we transit through Frankfurt, which normally wouldn't be an issue since we are vaccinated but Germany's recovery rule is at least 28 days. We can prove we are vaccinated to enter Germany but to prove we can get in the US we will have to show a positive test <28 days.

Will this make it so we can't board?

Thanks