1. Disconnect the members page from WP admin – Settings – BuddyPress – PAges – member , set it to none.
2. Create your members page in Elementor
3. Re-save this page as members page back in 1.
This has the potential to cause huge amount of spam on your site. I am not sure why would you want to disable this as this is an industry standard, also helps in confirming emails and communication.
p.s : In a commercial theme I use WPLMS, it has this feature of custom registration forms where this checkbox to disable account activation and log the user in automatically.