You can use the cohorts feature in users to identify those who have "session start" or "signup" or whatever you are measuring, and where the count = 1 vs count > 1. those who are repeat users will be in the > 1.
The key if you are trying to measure "longer term" repeat is to change the "last 30 days" that is default to something like "since 1/1/2025" or whatever date you want to use.
and for future reference, you can change the "total" to aggregate Property and do some other interesting stuff, like "distinct" and "time > month" to find those who come back on more than X months.
