If it’s a requirement to close a customer, they’ll tell you. Just keeping going with what you have until it blocks a deal you want to close enough to implement it.
Of course, many established companies offer SSO, ability to login using Google, Apple, other oauth.
I asked around to my test users and a few potential users and they mentioned email is fine. In my own experience as a SWE I used many softwares at work which used just email login. However, many more offered a bunch more.
Will it be fine to open it up to broader audience without all these things?