Ok, So I called IRCC again, hoping to get a different answer from a different agent and I got it. The portal is legit, the service team have received emails about it. I asked specifically with the link website name. Also, the portal has issues hence it has been taken down and they don't know when it will be up, it works for some and not for others. Regarding physical presence calculator, they confirmed that in paper application also it is no longer required to sign it.
I am going to wait a couple of days and see if they bring it back up else I'll go the paper route.