Newspaper un-installed itself

I have been working on an update of my site for some time, and finished today. Only thing left was to change categories on some posts. Great was my surprise when I returned to main screen from categories for testing. When previewing a page it only shows the script inserted from Newspaper. Looking closer I realize the Newspaper has gone. Plugins are not there.
That is, not completely gone. The Welcome/Plugins/Support pages are there, but the theme is not installed in WP. I tried to close down and reopen. No effect.
So what to do?
Can I just re-enable Newspaper, since the script in pages is there?
Anything else? I have used a few Cloud templates.

The environment is Bluehost/staging. Newspaper V 10.3.8
PS. Hope this not happen when I go live..

Here is last entry of error_log:
[27-Nov-2020 15:38:24 UTC] PHP Fatal error: Uncaught Error: Class ‘tagdiv_theme_plugins_setup’ not found in /home4/inditrav/public_html/staging/5397/wp-content/themes/Newspaper/functions.php:362
Stack trace:
#0 /home4/inditrav/public_html/staging/5397/wp-includes/class-wp-hook.php(287): {closure}(Object(Theme_Upgrader), Array)
#1 /home4/inditrav/public_html/staging/5397/wp-includes/class-wp-hook.php(311): WP_Hook->apply_filters(NULL, Array)
#2 /home4/inditrav/public_html/staging/5397/wp-includes/plugin.php(478): WP_Hook->do_action(Array)
#3 /home4/inditrav/public_html/staging/5397/wp-admin/includes/class-wp-upgrader.php(847): do_action(‘upgrader_proces…’, Object(Theme_Upgrader), Array)
#4 /home4/inditrav/public_html/staging/5397/wp-admin/includes/class-theme-upgrader.php(342): WP_Upgrader->run(Array)
#5 /home4/inditrav/public_html/staging/5397/wp-admin/includes/class-wp-automatic-updater.php(380): Theme_Upgrader->upgrade(‘Newspaper’, Array)

Hi Vlad
Thank you for your answer.
Just to clarify, the 4 tagDiv plugins are completely gone. Not to be found in \plugins directory. Pages and posts are there.
I can hardly think anyone should hack the site only to delete these, especially not in a staging environment. Live site has been ok for 3.5 years with another theme.
Regarding other plugins I have one new, W3 Total Cache. I disabled and cleared cache for this. Disabled also a few others. No child theme.
The good news is that everything came up as it should after installing tagDiv plugins again. Except for one strange thing, I have to regenerate thumbnails.