Drupal 8.x

How do I display a language switch link with the full content of the node, like Drupal 7?
I remember that links to all languages that have translations are displayed in inline text.

Is there some contributed module?
Should I create a custom module or a custom theme?

Thank you.

We installed two language switching switcher blocks and set them to UI and content respectively.
However, it does not work well. 

I probably do not understand the order of language negotiation, and I think its setting is not accurate.
What is the simplest way?

Thank you.

I've started working on optimization recently, and now I try to understand which CMS shows better performance with different tasks.

Theoretically, if the project I'm working on is mostly text content and I'll keep the same hosting provider, which CMS (Drupal or WP) would be faster? I'm not asking about forums, just blogs this time. Is there any statistics, for instance, side-by-side performance comparison? Or maybe someone have tested his/her project after migration and would be so glad to share the results?

I got a custom module called: ManageFinishDate

And the module name: managefinishdate.module

And the content type machine name I want this module to touch with: to_do_item

I recently switched from Acquia hosting to self hosting with Windows 2012 and PHP 7.3. I uninstalled the Acquia Connector module (https://www.drupal.org/project/acquia_connector) but Windows Event viewer is always reporting the following message now: 

Hi ! need help to fix this  :

Entity/field definitions