Hello Christian, I am so sorry!
The weird text indeed turned out to be in the Product Post Description. For some reason I did not see them, even thou I looked.
So now the situation persists as so:
1. In the backend, it correctly shares the TITLE on the post (as seen in the previous screenshots). However it still persists on the site logo for the image, my title is not added. But then, IMO in the backend this should really just be a placeholder and not working when clicking the share button. I am not even sure this is safe, given the history of Facebook of snooping data, I have no idea but I could imagine they are able to access the screen you share from, and in this case it would be the WP Backend. Which me personally I'd not want, and I really don't see the advantage of a functional share button in the backend... But let that be - it's just a quirk.
2. In the front end, instead of the Title it shares the excerpt, which is generated in my case from the post content (so that's why the mysterious strings, they where what seems placeholders in the post body(ies).
The site is online, so it should not be an issue with accessibility.
For us, here the most important right now (now that we know what the strange strings are) is the Featured image.
It would be really important that this setting is respected.
Note:
This is a WC Product Content Template. I did not test this on a normal post, and I did not test this on a clean slate, I did not have time for that yet.
I tested it on a other site though where everything is working smooth and there I got even worse results, the shortcode did not expand at all, see screenshot.
And it also clearly shows, it tries to share the [tb-dynamic provider='__current_post' post='current' source='post-excerpt' force-string='first' ] (excerpt) in the place where if shared from the backend it places the title.
Now, this might be expected, and the title would then be what we see in the actual "card", speak, the link text.
I also tested the Facebook debugger (they offer such a service) to see how it should look, and pretty much the same is the output as with Toolset, just that it tries to fetch OG data, which in Toolset case it shouldn't, since we have settings to force the image, title and descriptions.
It seems that exactly this is the issue, it still fetches OG data even we set the sources in the backend with Toolset, which should overwrite the OG Tag instructions, I believe, at least for Image, Title and Description.
I also tested with other dynamic settings and could confirm, it successfully respects the only thing that Facebook will NOT grab automatically, which is the text before their share card, which I assumed should be title but is the "Excerpt", that is working.
We can set it to anything in the Toolset blocks and it will reflect in the share
However, the title and image are not, they always default to what OG delivers to FB.
Sorry again I made you waste time with the "Do it" strings 🥲