front-end-output.php

Getting this warning in PHP, after updating to PHP 8:

Undefined array key "google_analytics_id" in 
/tag-manager-header-body-footer/include/front-end-output.php on line 69
Undefined array key "yandex_metrika_id" in 
/tag-manager-header-body-footer/include/front-end-output.php on line 70

Using WP6.0 and plugin version 3.0.0

Interestingly, we are only using this in the footer.
As a test, I put in an HTML comment in the header area, and the warning disappeared.
Then I removed the HTML comment in the header area, and the warning disappears.

So I suspect this happens on a narrow use-case, if you are not putting something in the header area, initially.