Website is broken because of plugin?

The plugin appears to functioning as expected but has added ugly notice messages displayed on page.

These files seem to be what is creating the mess:

class-strong-view-display.php
class-strong-testimonials-shortcode.php
Unsuccessful attempted remedies include:

Deactivated every plugin except Strong Testimonials
Deactivated, deleted then reinstall to latest Vers 2.40.6 Strong Testimonials
Same result when tested with Safari & Chrome on iOS, Android & a Macbook pro. I’ve run out of ideas – does any one have some suggestions?

Thank you in advance

Below are the messages I would like to not be seen:
Notice: Undefined index: mode in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-testimonials-shortcode.php on line 85
Notice: Undefined index: id in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 207
Notice: Undefined index: pagination in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 59
Notice: Undefined index: id in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 218
Notice: Undefined index: category in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 221
Notice: Undefined index: order in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 234
Notice: Undefined index: order in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 240
Notice: Undefined index: order in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 258
Notice: Undefined index: count in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 272
Notice: Undefined index: class in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 299
Notice: Undefined index: content in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 311
Notice: Undefined index: pagination in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 356
Notice: Undefined index: layout in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 367
Notice: Undefined index: layout in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 331
Notice: Undefined index: layout in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 332
Notice: Undefined index: pagination in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 356
Notice: Undefined index: layout in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 367
Notice: Undefined index: layout in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 452
Notice: Undefined index: layout in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 458
Notice: Undefined index: pagination in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 126
Notice: Undefined index: more_page_hook in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 136
Notice: Undefined index: more_page_hook in /home5/phildoug/public_html/wp-content/plugins/strong-testimonials/includes/class-strong-view-display.php on line 188
The page I need help with: https://www.phildoughty.com/

The page I need help with: [log in to see the link]