Drupal 8.x

I am working on a drupal 7 to 8 migration and ran into the next problem, I can't find a solution here, there are some links but no solution I can find.

In the D7 site I have about 15 different content types and some of them have a date field.
After the migration is done (Drupal 8 verision 8.6.5) all my date fields are filled in the DB f.i. table node__field_wedstrijddatum with field: field_wedstrijddatum_value is not empty.

But when i open an entity with the admin console this date field is empty.

Hi All,

I have a google map integration requirement in Drupal 8 where for all coordinate data to be exported entirely to a custom Google Map, where the location data will be handled. No location data will be stored in a Drupal Node. Therefore the name, address, number, email, website, latitude and longitude will all be stored within a custom Google Map.

Currently I am using below API to access the file from custom Google Map.

Hello Friend

I've faced an error that confused me 

in "Bootstrap Simple Carousel" when I add Unicode character i will get this error message " Incorrect string value"

I wrote just a few Arabic characters on caption title

Hello we have a production website with thousands of views each day. Sometimes we have to deploy our changes to production but during the deployment we are seeing 500 errors. After investigation I found out that when maintenance mode is switched on it throws an error for registered user, looks like something related to varnish.

My question is can maintenance mode be disabled during production deploy without any harm? If not can you please tell me how to avoid varnish in maintenance mode for registered users and show them static maintenance page?

I composerized existing Drupal site using

composer composerize-drupal --composer-root=. --drupal-root=/srv/www/htdocs/gsdb
composer require 'drupal/core'
composer require 'drupal/MODULE1'
composer require 'drupal/MODULE...'

Composer commands now work as expected, the site works normally, but with all Drush commands I get same error

How can I generate a dropdown of content types?   I have been searching and trying examples for 2 hours but everything seems to lead to generating a list of content type fields. The closest I have gotten so far is to generate a list of content types in a view but that only works when a piece of content exists for each type but then also lists the type of each piece of content resulting in duplicates.   I do not want the fields of a content type, I am seeking a top level list of certain content types (entities?) themselves for selection in a drop down.