Thanks for the updates. I was thinking there would be some URL (like domain-name.com/wp-login.php?action=entered_recovery_mode) which displays login screen without loading plugins (a plugin is causing issue, so if plugins are not loaded i can enter dashboard and fix it or even take a clone and move to another server). Or any other method which sends a recovery URL to email ID.(like a forgot password link). I even tried linking to Orion ManageWP but it didn’t work (as expected)
I gave up on recovering the site. Luckily domain access is with client. So, we will be developing from scratch and will host in some other server.