Hi Pablo,
Welcome to BuddyDev support forums.

You may use the following code and customize it as you need

/**
 * Customize allowed upload sizes for xprofile custom field types.
 */
add_filter( 'bpxcftr_allowed_sizes', function ( $allowed ) {
	$allowed['file']  = 64; // 64MB
	$allowed['image'] = 32; // 32 MB for image field.

	return $allowed;
} );

hope that helps.

Regards
Brajesh