Theme development

I read the following on Drupal on Sub-Theming:

You should never modify any theme or sub-theme that is packaged and released from Drupal.org, such as Drupal Bootstrap. If you do, all changes you have made will be lost once that theme is updated. Instead, you should create a sub-theme from one of the provided starterkits (this is considered a best practice). Once you've done that, you can override CSS, templates, and theme processing.

My question is the following:

Hello, I am totally new to Drupal and have a couple of questions:

1) Should I be installing Drupal 8 or Drupal 9?

2) If I install Drupal 9 (assuming I'm going with 9 since it is the latest version), should I install Bootstrap 3 or Bootstrap 4?

3) What are some of the best free themes for Drupal 9? I've searched on the web but everything seems to refer to Drupal 7 or 8..

Thank you!!

Hello everybody .

I have a content type motorcycles . In that a Term reference field  for the brand  of the motorcycle .

I have a made a page view ( exposed form in block )  to search for a particular brand of a motorcycle . In FILTER CRITERIA i have an exposed filters using simple hierarchical select ( content:has taxonomy terms ( with depth ;simple hierarchical select (exposed ) .So that works fine , a dropdown menu shows with the vocabulary terms of the brands and types .

Hi guys,

I try to retrieve NOT the id but the content of my taxonomy but I can't find how to access the content. I only get the 'target.id' in my unformatted view.

However, in my view I retrieve a type of content where the taxonomy exists.

In my view :

I have a Drupal 8 template file with the following markup.

<div class="col-4 col-sm-4 col-md-4 col-lg-4 col-xl-4 p-0 text-center">
  <i class="far fa-heart fa-lg"></i> {{ product.flag_like_product }}
</div>

Is it possible to exclude the following markup?

I have created 2 accordion menu for Bootstrap.

But it doesn't work properly.

I want when I open an accordion menu, it will close the other accordion menus.

How to do this ?

Le menu `accordionSetting` doit ouvrir un accordéon à la fois dans ce même menu.