It seems like there is no fixed timeline for people who have applied for PR card via post. I know many folks who are waiting since Jan 2021 and have not received their card. Since a lot of people are curious to know the process and timeline, I have created a WhatsApp group so that we all can keep ourselves updated.
Please note this group is meant for people who have sent their photos for PR card via post.
https://chat.whatsapp.com/FPe2pNjDdhu2afi0RbmQ2q