Drupal 8.x

I do my Drupal development on my home OpenSUSE Linux machine. I just updated it from LEAP 15.1 to LEAP 15.2, but now none of my D8.9.1 or 9.0.1 instances can connect to their databases. I know this because "Drush was unable to query the database".

phpMyAdmin lets me connect, and the databases are all there, as are the user accounts. But phpMyAdmin says

Hello!

today i made an update to 8.8.9, now I get a blank page with "The website encountered an unexpected error. Please try again later.", nothing else.

The error-logs:

I have several sites that I want update.
I'm updating the first one.
This has ZURB Foundation 6 8.x-6.0-alpha6 theme installed and it has subtheme.
It has some overriden html.twig files and css and js code to customize the subtheme.

I used the command "npm start" en th subtheme directory and it shows this error:

I want to hide a block under certain conditions. The code works, but only if I flush the caches after the condition changes. I guess I have to do something with the cachablity of the block, but I'm not sure how. Any ideas?

Here's the code:

Hello!

in a really short time, my cache exceeds the db limit.

For example, now it took just 2 hours and the cache_dynamic_page_cache growd to 363,8 MB, the cache_page to 334,2 MB and the cache_render to 162,3 MB. So the site is down.

After some optimization the module database optimization says "The size of all tables in the database: 230.69 MB.". The provider backend tells "317 of 1024 MB in use".

So there is a difference.

What could be the reason and how can I solve this one?

Hello,

I am trying to create a nested accordion from content titles.

Is there a module or a technique that I can use / follow?

Thanks in advance

Christoforos