Thanks for leaving a detailed explanation! Luckily I managed to get it working, from the other post I wrote, with the help from @michaldybczak. Now I’m able switch without using bbswitch, I’m just using the None mode and it works. I’m adding a summary of what I did(of course all credits go to the people who helped me):
- Uninstalled all the drivers configurations, and reinstalled
video-modesetting and video-hybrid-intel-nvidia-450xx-primeusing the commandsudo mhwd -a pci nonfree 0300. - And then simply followed this guide again.
- [For
gdmusers], Installlibgdm-prime(probably this did the trick not sure). - Added a kernel boot parameter using this post: How to Choose the Proper ACPI Kernel Argument (Not sure if this affected anything but it’s worth giving a shot I suppose).
And that’s it. I rebooted my system and I could login in with no issues using the intel driver.
However, switching using nouveau didn’t seem to work, it just led to the company logo, however I logged into a tty session, Ctrl + Alt + F6 in my case, and switched back to the main tty (Ctrl + Alt + F1), and I could see the login screen again. Voila, it works. Yes it’s a workaround, but I’m happy it works.
Later I tried switching using the None option and I can confirm that it works for me. I could now delete bbswitch without any login issues. So bye bbswitch.
I don’t know either, I haven’t tried stopping/disabling it, but it works.
Yes this was all my fault, if only I had installed the correct version for bbswitch, I probably wouldn’t have faced these issues. Lessons learnt, I won’t do this again. Thanks! 
@XRaTiX, @anon89812132 thanks for the valuable inputs, I’m ever so grateful for this community that can tolerate noobs like myself, and lend a helping hand.