Cannot edit theme files via theme editor

I am trying to edit theme .php files via theme editor, but getting the following error:
“Something went wrong. Your change may not have been saved. Please try again. There is also a chance that you may need to manually fix and upload the file over FTP.”

Now when I edit any other theme files it works fine.

We had changed the dazzling theme folder and files to have the same ownership and permissions as the other themes, but to no avail.
What else can cause this?

When customizing the appearance of the theme, and clicking the “x” button on the top left it does not redirect me to the proper place and gives this error: No route matches wp-admin/themes
it forgot to put a blog/wp-admin/themes

Good morning

Sorry but none of the thiese problems are theme related, they are related to your hosting file permissions and WordPress, you may have exact same issues on any WordPress theme, try to research your question in the internet or contact to your hosting support