Test Environment
Tested on smart phone, Lenovo Moto g6plus

1) Form with 20 Signature Fields, Joomla Template Protostart, BF Template default 
Result: Performance ok

2) same as in 1) plus  Frontpage Editing via ContentBuilder Integration.
List View, Code for each Signature Field Element:
<?php $value = '<img src="'.Juri::root(true).'/media/breezingforms/signatures/'.$value.'"/>';?>
Content Prepare:
$items[„s1"]["value"] = '<img src="'.Juri::root(true).'/media/breezingforms/signatures/'.$items[„s1“][„value"].'"/>';
$items[„s2“][„value"] = '<img src="'.Juri::root(true).'/media/breezingforms/signatures/'.$items[„s2"]["value"].'"/>';
.
.
.
$items[„s20“][„value"] = '<img src="'.Juri::root(true).'/media/breezingforms/signatures/'.$items[„s20“][„value"].'"/>';
Result: Performance ok

3) same as 1) plus added visibility rules
Result: --> performance bad, but only if all elements are initially set to invisible
4) same as 2) plus added visibility rules
Result: --> performance bad, but only if all elements are initially set to invisible

5) same as 1) but: no vis rules for sig elements, only vis rule for different elements
Result: Performance ok
6) same as 2) but: no vis rules for sig elements, only vis rule for different elements
Result: Performance ok

7) sam as 1) but: control visibility of signature fields via script
Result: --> performance bad
7) sam as 2) but: control visibility of signature fields via script
Result: --> performance bad