If you have an email list you can import it and use for retargeting. You can also create a lookalike audience based off that email list. Worth mentioning is also a fact that sometimes a new Facebook Ads account will have limited access to such functionality, at least according to Facebook Ads documentation.
After the campaigns run for some time and generate some results – then it’s a good moment to create a lookalike audience based on that. The more data – the more accurate the lookalike audience will be.
If that’s possible – start with retargeting email list and create lookalike audience from it.