There isn’t any way to hide the repeater field so that it does not load. There is a plugin that will collapse them https://wordpress.org/plugins/advanced-custom-field-repeater-collapser/
There is not limit to the number of rows you can have in a repeater except for settings in PHP and the physical limits of your server. There is a php setting named max_input_vars, if you go over the value of this setting then the excess rows will be ignored. There is a plugin available that will tell you when you’re exceeding the setting. https://wordpress.org/plugins/wp-max-submit-protect/
