I recently graduated (MSc from a Dutch technical university) and started working in the Netherlands last February 2021. I earn ~36k/year and I received housing and healthcare allowances during my studies in the Netherlands. Am I allowed to sponsor my wife (American citizen) and reunite in the Netherlands?
As long as you are not a Dutch citizen, your wife can join you in the Netherlands under EU law. All the restrictions that apply to the spouses of Dutch citizens and third-country citizens do not apply to you.
She should travel to the Netherlands without a visa, carrying proof that she is the spouse of an EU citizen. She would then apply for a “Toetsing aan EU-recht” at the IND.