Hi @Kush1
I would recommend to review this community post regarding the matter.
Also, regarding the default login URL setup for native apps, I can see that my colleague has shared a knowledge article related to that on the post you have bumped up previously.
Otherwise, you can also have a browser based controllers approach since they will be able to handle the invitation links that you will be sending to the user.
If you have any other questions, feel free to let me know!
Kind Regards,
Nik