Per the table in UWorld qid 4875: alpha/beta thalassemia minor has normal or INCREASED RBC count. Per the AMBOSS link which you referenced: alpha/beta thalassemia has “higher RBC count than iron deficiency” (although this is a really vague way of wording it).
While it is true that thalassemia minor patients don’t always have anemia, the reason is because an elevated number of RBCs cancels out the reduced size of them, such that hematocrit/hemoglobin is within normal limits or only slightly decreased. Total RBC count is not the only determinant of hemoglobin/hematocrit and anemia.