loading page time too high

Hi, I have a lot of cb fields on my site (up to 300). I used CB conditional to show and hide fields, but when I edit a profile loading page time is too high, maybe because it loads all fields, also those useless.

How can I solve this problem?
Thank you

You have 300 fields being conditioned by JS. It's going to be slow. There's no getting around that. That's a absolutely massive amount of input elements for a <form in general, but significantly more for JS to have to condition.

How can I solve this problem?

Reduce the number of fields you're using. It's important to think of why you need that many fields and how you can reduce the strain on your users to deal with that many fields.

I can't reduce the fields, every user must have the chance to edit up to 300 fields depending on the conditions, maybe in most cases it will edit only 5 or 6 fields and then displaying only 5 or 6 fields , but the user must have the way to edit them all.

You're conditioning over 300 HTML elements to show/hide. That's heavy for JS to have to do. Each fields is roughly a total of 5 elements to hide. So that's 1,500 HTML elements with displays being conditioned. To confirm if the conditions JS is doing it unpublish CB Conditionals then see if your performance issue persists.

Yes, if I disable cb conditional plugin, the performance issue is solved, but all fields appear

Then you've too many fields being conditioned. You're changing the DOM state of so many elements with JS it's going to be slow. It's not server performance though, but the browser is choking due to JS performance. You maybe able to improve the performance by using tab conditions to condition entire tabs instead of individual fields. You can also disable value resetting in CB Conditional > Parameters as it resets the input value on hide, which also takes additional JS parsing.