Drupal 8.x

Hello,

I am looking how to put a Field from Node's form into a separate Region, probably through block / views.....

//I mean - a block that displays on a Node /#345 a field from #345 in a separate block and on other nodes their respective field....

Once I read such an instruction on internet, but that website is down now and I cannot find this....

I think it was done by assigning Contextual Filter or relationship by ID in Views, but I cannot remember all details, if you know, please help....

In a Content Type I need 2 fields now.
In a 3 field I must have the difference between the time of arrival and that of departure.
In order not to install a new module, I would prefer to use the DateTime field but as far as I could see the date field I cannot hide it.
Any suggestions?

Hi, I am trying to update from core 8.8.4 but whatever I try, I am stuck.

Here is my composer.json

Drupal 8.8

In a C.T. I have various entity reference fields and set them with a value taken from another C.T.
The problem is that I can only set it in this way 

$a = Dato();

$form['field_a1']['widget'][0]['target_id']['#value']   = $a;

and it works

Instead I would need to set it in this.

$form['field_a1']['widget'][0]['target_id']['#default_value']   = $a;

but it does not work