Drupal 6.x

I have a site that has been running for about 10 years. I think it was Drupal 6. It was hacked up pretty good, and although I have *some* proficiency, it's been a long long time since I developed. 

The site finally completely broke, and I am unable to get into the UI. Homepage returns a 500 error. Nothing has changed on the site for at least 5 years.  I traced it down, and it looks like it is failing on a syntax error from mysql. It looks like something was changed or deprecated between mysql, and the database functions.

Greetings,

In the past we were attempting to do a clean installation of higher Drupal version, add to that new instance the Node Import module, and to extract from the old D6 instance the content into the clean D10 instance. Unfortunately Taxonomy numbers always ended up getting scrambled.... so a few sites are still stuck on D6.

I see Node Import has been deprecated, and suggestion to use Feeds instead.

Is it still a recommended workflow to:

1) Install fresh latest D10

Hello! My name is Conrad, dont know drupal, just making maintenance to a small website who runs on drupal 6.19.

Recently the website started giving error  - ini_set () cannot set user save handler by ini_set or session_module_name on line x in settings.php I googled it and deleted the line, now the website can be accesed, but with errors. I need to login in the website interface to modify some pages and gives multiple errors "Parameter must be an array or an object that implements Countable" and also username or password error. " The user and password are correct.

I am a retired university lecturer who has used Drupal for nearly 20 years to create websites to satisfy my various academic, professional and hobby interests, including hi-fi, table tennis, rental property advertising and management, provision of online courses, and any other topic which took my interest at the time.  Currently, I am using Drupal version 10 for the first time to create a website for an association of former colleagues.

I have a running drupal 6x site which

- let user have his own blog (this set-up happened super easily and by default in D6 very intuitively with default menu link to individual blog in each user profile page)

- with help of a module, shows in a side bar - month-wise links to each month blog posts were posted

- allowing each user to save his own favorite posts, and this selection could be shown to others from a link in profile page (?watcher module)

To see some revisions I'm getting "Internal Server Error".

In the logs I see this:

[Mon Jan 16 15:20:45.832899 2023] [fastcgi:error] [pid 16941:tid 140623360337664] [client 157.38.113.58:42646] FastCGI: comm with server "/usr/lib/cgi-bin/php5-fcgi" aborted: idle timeout (30 sec), referer: 

It's Ubuntu 14/Apache/2.4.7 with php5-fpm.  I've edited /etc/php5/fpm/php.ini max_connection but still not able to work out