Post installation

I will add a legal notice that everything in my website besides WikiCommons images is copyrighted in my own custom copyright license but besides this legal issue, how to bring images from WikiCommons to a Drupal node correctly and properly?

In a MediaWiki website, I would just paste this:

[[File:Maralago1 (4158314102).jpg|thumb|right|Description]]

Or, if I want to create a gallery, I would just paste this:

It would be hugely helpful to my writing workflow (which begins in Obsidian) if I can paste Markdown text into the CKEditor window. It can accept typed MD, but not pasted.

In the docs, I found this feature which needs to be enabled. Is it possible to enable that in a Drupal installation? If so, ELI5 if possible, please!

I can't add themes or modules via the Drupal admin UI. I finally found that it was because the Update Manager module in Core wasn't turned on. I tried to do it, but got the error: 

Unable to install Update Manager, update.settings already exists in active configuration. 

Recipe: in Admin, go Structure -> Menus, and click on the "Edit menu" button to the right of "Main Navigation", the in the menu editor click the "Edit" button under "Operations".

Here that results in a 443 error, and understandably so since this is the URL:

https://domain.com/admin/structure/menu/link/standard.front_page/edit?de...

I'm working on a project using headless Drupal and successfully set up a new custom view to act as the API endpoint for retrieving content. Everything works as expected and I'm able to get content by its node ID, but I was hoping to be able to get content by its taxonomy term instead. I can use the taxonomy term ID and that works, but ideally was hoping to use the taxonomy term itself (i.e. the tag) to get all content with the tag. Is there a way to set this up?

This seems to be a simple question but I cannot find an answer, and believe me I have tried – a lot.