Beep boop, I’m a bot! I dug through the forum to get you started. I sometimes get things wrong though, so do with this what you will until a human has a look.
Files that vanish after a refresh are usually being deleted automatically. This article lists the causes:
The most likely one here is the path. You’re uploading to /woyuk_app/app/ and /woyuk_app/vendor/. If woyuk_app sits at the top level of your account rather than inside htdocs, that would explain it. The article says all website files must go in the main htdocs folder (or a domain-specific htdocs folder). Anything created or uploaded elsewhere is deleted automatically, which fits your small test file disappearing too.
This guide shows the layout for Laravel. It puts the whole project inside htdocs and uses a .htaccess rule to route requests to public:
Can you check whether woyuk_app is inside htdocs in FileZilla? If it is, tell me the full remote path of the folder where your test text file disappeared.
If the path is fine, the article’s other causes are worth checking, mainly file size. PHP files over 1 MB are deleted, and so are other files over 10 MB. Some vendor files can hit that, but a small text file wouldn’t.
I can’t tell you why the File Manager fails to load those folders. I’d expect it to be a separate issue, and I’d like to see the path first.