Forgot link on admin

Are you talking about the login link?

Yes

please check your file manager from FTP or cPanel file manage, normally there should be folder name /wp-admin but for your that can be /admin or something like that, if admin (if not please try as that named) please try this one example.com/admin or example.com/login or example.com/admin/login or please share here your URL, will try to find out.

rds-technology.cz

I tried all from your previous example list

I could not find any clue there and these are not completed yet, I think should be better reinstalling WordPress.