Theme development

I am running Drupal 10 with Domain Access and was playing around with themes.

First, changing themes with domain-specific configuration wouldn't always work. Changing the theme with domain configuration disabled would work, for all subdomains.

Then, I tried the Domain Theme Switch module. Themes would change, but I could not configure them.

Hello,

how is it possible to get the #markup value for twig treatments, before it could be formatted by other processes than the 'human_decimal' I need?
dump() show this structure:

I have twig suggestions turned on, and I need to make some display mods for the table.

The output is:

BEGIN OUTPUT from 'core/modules/views/templates/views-view-table.html.twig'

However, there are no suggestions.

What I tried in my theme folder were the following:

views-view-table-[viewname].html.twig

views-view-table-[viewname]-[block_x].twig

But none of these seem to work.

May I ask about best practice. Say I have a content type called Widgets and then I want to have a Widgets page which has a title, maybe some photos and a text based introduction and then below a list of widgets in a grid. I have always created a Basic Page where I have added my introductory content and then I have created a custom page template where I have added a block (which is a views block listing the widgets I want displayed. Is this best practice?

Hello,
a 'test' content type has an integer field with prefix and suffix.

How can the Layout Builder be employed to craft a Drupal layout resembling the puzzle-style arrangement depicted in the image "Web 1920 – 1.jpg ," where the sidebar operates as a region content managed by the Layout Builder? What particular challenges emerge in this scenario, distinct from the standard two or three-column layout conventions as illustrated in "Web 1920 – 2.jpg"?