Failure to open

While updating my wordpress site yesterday I received a message saying that the wordpress service was undergoing maintenance and to check back in a min. After waiting a while I received the following and my site will not load. I assume that it is the blog/blog-config.php file that is not working but it appears that it is a failure of the Astra theme.
Someone suggested the following: Access your server via SFTP or FTP, or a file manager in your hosting account’s control panel, navigate to /wp-content/themes/ and rename the directory of your currently active theme. This will force the default theme to activate and hopefully rule-out a theme-specific issue.
Thanks for the help.
I can navigate to /clickandbuilds/TheLift111/wp-content/themes/astra folder in my Ionos web host, but if I change the name and force the default theme to activate, won’t I lose all of my work that I have done on the site? Sorry, I’m fairly new at using WordPress. Any help would be appreciated! Mike

Warning: require_once(/homepages/46/d892060657/htdocs/clickandbuilds/TheLift111/wp-content/themes/astra/inc/blog/blog-config.php): failed to open stream: No such file or directory in /homepages/46/d892060657/htdocs/clickandbuilds/TheLift111/wp-content/themes/astra/functions.php on line 86

Fatal error: require_once(): Failed opening required '/homepages/46/d892060657/htdocs/clickandbuilds/TheLift111/wp-content/themes/astra/inc/blog/blog-config.php' (include_path='.:/usr/lib/php7.4') in /homepages/46/d892060657/htdocs/clickandbuilds/TheLift111/wp-content/themes/astra/functions.php on line 86

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