Can I travel to Austria if I got vaccinated recently?

The latest travel rules to go to Austria, as of today, say something like this: you can enter in the country as long you have one of these proofs:

1. Vaccination certificate + negative PCR test, or
2. Vaccination certificate + third booster dose
3. Confirmation of a recent COVID infection + negative PCR test

The above is the summary of the travel regulations from mae.ro – you can find a similar one here.

Now, here is my dillema: I got vaccinated recently, hence cannot take the booster dose.

Theoretically I should do the PCR test, but I am wondering if there an exception for this case (recent vaccination)?

At least, I would expect that the booster dose is to increase the immunity after x months, but being freshly vaccinated, I would expect I already have a good enough protection.

Not sure if it matters, I will travel by car.