Every checkbox is a decision. Every decision is friction. More frictions means fewer submissions.
"Sign up for our newsletter" check
"Agree to partner offers" check
"Get community updates" check
"Receive SMS notifications" ...
At some point, people stop filling out your form and start playing defense against it. You need a better strategy. Keep what's legally required or genuinely useful and cut everything else.
The smaller the ask, the greater the success rate.