My reluctance to using a hosted auth system (vs using passport or similar) is vendor lock-in. My impression is trying to move later would reset all passwords an

My reluctance to using a hosted auth system (vs using passport or similar) is vendor lock-in. My impression is trying to move later would reset all passwords and oauth connections to zero. Am I misunderstanding this / should I not really be concerned about this? Would definitely make my life a lot easier.