I worked for a US media company that forced us to use a half-baked CMS from a Norwegian software company, with no apparent provisions in the contract for updates or support. The CMS was absolutely terrible to work in. Just one small example: It forced every paragraph into a new textarea, so if you were editing a longer news story with 30 or 40 paragraphs, you had to work with 30 or 40 separate textareas. So I basical…
One hack I remember that fit this thread, is someone using Enonic as a headless cms long before headless cms was a thing. Basically every string in their frontend apps had a key, and that key was a hierarchy of articles in Enonic. So a whole "enonic article" for every single piece of text, like, every button, heading, menu element was backed by its own article.
That meant that the editors could edit any piece of text in the SPA from Enonic. An article in /cms/myapp/something/myelement we then would export to the key myapp.something.myelement, and we did that for all ten thousands of small text string articles, and then built that into the SPA with a sync job running regularly.
We also had a way to turn off templating in the SPA. Appending ?showKeys or something to the url would print the keys instead of the content, helping the editors know which article to edit for that element on the page.