Is 1.5cm dilation at 22 weeks pregnancy is Cervical incompetency? Usually heard that cervical dilation at 20-50mm is incompetent. What is true?

Controversial topic. Premature cervical changes(dilatation,shortening, funneling,softening...) are difficult to measure and to interpret.Sonographic or clinical exams of your cervix are very variable, very subjective, not accurate nor reliable predictors of premature labor or preterm delivery. Consult a knowledgeable MFM doctor regarding accepted criteria for "cervical insufficiency". Your risks at 22wks.seem small.
Only OB doc can tell. I strongly recommend getting the answers from the OB/GYN team caring for the pregnancy. Try to avoid any unnecessary stress as that may negatively impact pregnancy outcome.