Hey there @ellis.carvalho , thank you for posting!
I’m happy to assist with this question.
Currently, in case you would like to consider such an option, you could write Actions script (node js) to gather log in / sign-up events context and send it to your external analytics service.
Another option would be implementing Google Analytics on the Login Page - here is the Knowledge Article on how to do that and what you could measure with that - Add Google Analytics to New Universal Login
Please let us know if you have any other questions!