Module development and code questions

For the moment, each authenticated user generate a specific page cache (node entity) when he navigate on the website. 

Is there a possibility to use the same cache page (news node) for all users with a specific role (eg editor) ?

Do I use the cache_api for this ?

Thanks for yours examples and replies.

I created a new types of content (import) to which it imports data from CSV files. 
This node contains the field (field_result) in which the value is stored.

I added views that displays all nodes in the form of a table.

I want to add programmatically three rows to the view: sum, average and min

Now the table looks like this:

| Node name | field_result
------------------------------
| node1         |  3
| node2         |  5
| node3         |  2
 

I have nodes with puzzles. I store extra info on the puzzle (say puzzle_sol) in a different table. I add this extra info to node in 'hook_node_storage_load' in my module. I then attach a special library to the page in page_attachments hook. There I use the above extra info to decide whether to attach the library or not. (if puzzle_sol was added, then attach the library ... else not)

This whole strategy is working without absolutely any issue.

Now the problem.

I am currently trying to patch a module so that you can use the local oembed thumbnail to display as a preview.

Currently the direct url to the youtube thumbnail is used but that is, of course, not allowed by DSGVO/GDPR cancer.

My idea was to use the hook and load the thumbnail there. But OEmbed::getLocalThumbnailUri is a protected function.

Any ideas hints or tips? Any contrib doing this where i could read some code? Thank you.

function hook_preprocess_media_oembed_iframe(array &$variables) {

Background:

I am using hook_node_access_records() , and hook_node_grants() in a custom module for node acces control and it Works perfectly

I am wondering if there would be something similar for media entities??

Thanks in advance for your advices.