it is highly desirable to limit user registration to a check for meaningful action
now the site is under a relatively light attack by spambots - 20 users a day, more than 5000 senseless accounts with only 43 active (only 200 hosts for this whole horde)
in the future, the attack rate can grow up to hundreds of thousands of registrations per day.
these accounts clog the database, and over time are activated to send advertisements - messages in the forum, advertisements in profiles and in fictitious teams, etc.

the solution can be found at https://boinc.berkeley.edu/trac/wiki/ProtectionFromSpam
in short, it can be a recaptcha on the registration page or a requirement for an invitation code, which is on the same page or on the main page
(you can give it with a breakdown with invisible tags to complicate automatic reading - as on sites usually give an e-mail)

these are simple solutions for the first wave.
then you will have to clean the site from bots - without connected hosts, blacklisted e-mails, etc.
restrict the creation of a profile or team only if the user has credits

Thanks for the suggestions