If you are a low skill, you will never have the right to apply for PR unless you are in the right low skill job in AB or BC and apply with employer support through PNP. The rules for low skill say that you have to leave for 4 months after 2 years before you can apply again but even if you managed not to do that through some glitch in the system, it will still not give you the right to get PR.
If you are a skilled or you managed to get promoted to skilled, you can apply through PNP or work 2 years and apply through CEC.