hi i saw this solution does it help?
edited :
If you create a new profile group, then you could move some of those profile fields to these new groups and it won’t show up on all a once in the registration page.
To create a new profile group, login to the WP admin dashboard and navigate to “BuddyPress > Profile Fields” page. Next, click on the “Add New Group” button located in the header text.
here is the link
https://buddypress.org/support/topic/register-page-limit-number-of-profile-fields-shown/
