Please, I need help to get the recover cart module working on ZC 1.5.8 so I can upgrade production sites and I do not have enough php knowledge to fix the errors occurring.

I am currently testing with this configuration:

Server: Ubuntu 20.04 PHP 8.1 MySQL 8.0.31 (I have ran ZC for many years but I did confirm all recommended server requirements are present just in case something changed with 1.5.8)
Test Site: Zen Cart 1.5.8 with the exception of the Recover Cart 4.0.6 being tested no additional modules have been installed and no demo data (I have found there is a problem with the 1.5.8 install that changes the ownership of the demo images/folders added during the install process to www-data blocking sftp manipulation, if you change them back to the correct owner it breaks image display). I have created a couple of categories and items to provide data for recover carts.
Test Site url: a l t 1.h u m p h r e y s t o w b a r s.c o m

The Recover Carts module is currently using all default setting from the installation.

After install when I drop down Customers and Click Abandon Carts I get a blank page and this debug error: (I changed the domain and admin folder hoping to make this easier to read)

Code:
[22-Nov-2022 14:22:04 America/Chicago] Request URI: /admin/index.php?cmd=recover_cart_sales, IP address: 98.190.184.37
#0 /var/www/domain.com/public_html/admin/recover_cart_sales.php(37): zen_debug_error_handler()
#1 /var/www/domain.com/public_html/admin/recover_cart_sales.php(37): require()
#2 /var/www/domain.com/public_html/admin/index.php(11): require('...')
--> PHP Warning: require(includes/languages/english/mail.php): Failed to open stream: No such file or directory in /var/www/domain.com/public_html/admin/recover_cart_sales.php on line 37.

[22-Nov-2022 14:22:04 America/Chicago] PHP Fatal error:  Uncaught Error: Failed opening required 'includes/languages/english/mail.php' (include_path='.:/usr/share/php') in /var/www/domain.com/public_html/admin/recover_cart_sales.php:37
Stack trace:
#0 /var/www/domain.com/public_html/admin/index.php(11): require()
#1 {main}
  thrown in /var/www/domain.com/public_html/admin/recover_cart_sales.php on line 37

[22-Nov-2022 14:22:04 America/Chicago] Request URI: /admin/index.php?cmd=recover_cart_sales, IP address: 98.190.184.37
--> PHP Fatal error: Uncaught Error: Failed opening required 'includes/languages/english/mail.php' (include_path='.:/usr/share/php') in /var/www/domain.com/public_html/admin/recover_cart_sales.php:37
Stack trace:
#0 /var/www/domain.com/public_html/admin/index.php(11): require()
#1 {main}
  thrown in /var/www/domain.com/public_html/admin/recover_cart_sales.php on line 37.
After researching I found that (admin)'includes/languages/english/mail.php' had changed name to lang.mail.php.

I changed the end of line 37 to: '/' . 'lang.' . FILENAME_MAIL . '.php');

which cleared this error, and I do not think it will cause additional problem since it is simply correcting the name of the file required.

Now when I click Abandoned Carts I get the top portion of the page down to the subject line and I have the following error in the debug logs.

Code:
22-Nov-2022 14:37:51 America/Chicago] Request URI: /admin/index.php?cmd=recover_cart_sales, IP address: 98.190.184.37
#0 /var/www/domain.com/public_html/admin/recover_cart_sales.php(41): zen_debug_error_handler()
#1 /var/www/domain.com/public_html/admin/index.php(11): require('...')
--> PHP Warning: Undefined variable $action in /var/www/domain.com/public_html/admin/recover_cart_sales.php on line 41.

[22-Nov-2022 14:37:51 America/Chicago] Request URI: /admin/index.php?cmd=recover_cart_sales, IP address: 98.190.184.37
#0 /var/www/domain.com/public_html/admin/recover_cart_sales.php(47): zen_debug_error_handler()
#1 /var/www/domain.com/public_html/admin/index.php(11): require('...')
--> PHP Warning: Undefined array key "action" in /var/www/domain.com/public_html/admin/recover_cart_sales.php on line 47.

[22-Nov-2022 14:37:51 America/Chicago] Request URI: /admin/index.php?cmd=recover_cart_sales, IP address: 98.190.184.37
#0 /var/www/domain.com/public_html/admin/recover_cart_sales.php(58): zen_debug_error_handler()
#1 /var/www/domain.com/public_html/admin/index.php(11): require('...')
--> PHP Warning: Undefined array key "action" in /var/www/domain.com/public_html/admin/recover_cart_sales.php on line 58.

[22-Nov-2022 14:37:51 America/Chicago] PHP Fatal error:  Uncaught Error: Undefined constant "TEXT_MESSAGE_HTML" in /var/www/domain.com/public_html/admin/recover_cart_sales.php:541
Stack trace:
#0 /var/www/domain.com/public_html/admin/index.php(11): require()
#1 {main}
  thrown in /var/www/domain.com/public_html/admin/recover_cart_sales.php on line 541

[22-Nov-2022 14:37:51 America/Chicago] Request URI: /admin/index.php?cmd=recover_cart_sales, IP address: 98.190.184.37
--> PHP Fatal error: Uncaught Error: Undefined constant "TEXT_MESSAGE_HTML" in /var/www/domain.com/public_html/admin/recover_cart_sales.php:541
Stack trace:
#0 /var/www/domain.com/public_html/admin/index.php(11): require()
#1 {main}
  thrown in /var/www/domain.com/public_html/admin/recover_cart_sales.php on line 541.
Which up to this point I have had no success in resolving.