183 day rule per calendar year, EU passport

Hola todos,
Am I thinking this through correctly?

Wife and I both hold EU passports (German citizens, living in the U.S.). We arrive in Spain in, let's say August 2026 as an example. After 90 days, we need to register at the Oficina de Extranjeros.

In this example, 150+ days will have passed by end of year 2026. Does the 183 day rule then reset beginning January 1, 2027? So, technically we still would not be considered a tax resident until June/July 2027? I work remotely and would then want to register/obtain NIE if we decide to stay.

Im asking as we would like to give a trial period of 'living' in Spain for several months before deciding. We have visited beautiful Spain several times and speak ~B1 level.

Thank you for any info/suggestions.