What I'd like to do is build a page with two things:
- On one half of the page, custom markup with data from Drupal.
- On the other half, a custom form also submitted to Drupal.
There are a lot of tutorials on how to programmatically build pages in D8 (create route, extend controller, return render array, etc.). There are also a lot of tutorials on how to programmatically build forms on D8 (create route, extend form base, return render array, etc.). However, I could not find any resource on how to build both onto the same page.
How would I go about doing this?