IF I understand your post correctly, Typo3 does not have some kind of plugin for structured data. Which I find pretty sad, since I've com to know Typo3 as a very stable and well coded CMS. Unfortunaltely, I only work with WP.
Right now, I have a customer who has a Typo3 Site which I want to optimize with some Schema Markup.
I've even managed to do this with Wix CMS, and it works fine, although it's a real pain to create all the JSON LD Scripts and insert them in the site using a html box.
But I can imagine this is possible with Typo3 too by using the text editor and inserting the code manually.
Unfortunately I haven't been able to test this yet since I do not have Access to client site (yet).
I've seen big ranking improvements on client sites, after using some more advanced schema markup. Advanced means : More than these Plugins create automatically, but even these simple markups bring nice results...
Hope it helps.