It sounds to me like your server maybe be having some issues. A lot of hosting providers had to do a lot of extra work for new EU regulations – it wouldn’t surprise me at all if something got disturbed during all that work.
I think probably your first stop should be a support email to your hosting provider to ask if anything has changed.
But secondly, a little advice when posting about an issue here on the forum: Please be as detailed as you can about what you’re doing. Post the specifics of what you did and what you saw. Let me try to give an example…
I uploaded also the whole site to a new subfolder
There are three ways to publish content within RapidWeaver and you mentioned you also use an FTP app – so there are for possibilities of what you were doing here. If they are inconsequential differences the experts here on the forum can ignore those bits. If they are important, it might help to identify the issue.
I have made a small text change on this page, but it does not appear after updating.
Did the change not appear when you browsed to the site?
Or when you checked with your FTP app?
Or did RW say that it didn’t publish?
What change did you make?
What was the URL of the page?
All the little details you can provide give experts a bit more info and sometimes can be the key to uncovering a problem.