Thanks to Margy for the tip.

As long as they work, I shall keep using them. Use these direct links to reach the old post and page dashboards on wordpress.com, and the classic editor for editing. If you're on wordpress.org, install the Classic Editor plugin, it removes the block option completely from the dashboard.

New post:

https://[yourblog].wordpress.com/wp-admin/post-new.php?classic-editor

All posts:

https://[yourblog].wordpress.com/wp-admin/edit.php

New page:

https://[yourblog].wordpress.com/wp-admin/post-new.php?post_type=page&classic-editor

All pages:

https://[yourblog].wordpress.com/wp-admin/edit.php?post_type=page

All right, here is my duh brain moment. You can revert to the old interface via this option. Hit Screen Options, then select Classic. The downside is you have to do it for every category. But once you have, it should remember your choice.