import re
text = '123 !"§$%&/()= äüöüÄÖÜÄßßßß hello-123, hello-hello, hello-.'
print( re.sub(r'-?\d+-?|[^\w -]|_|-(?!\w)|(?<!\w)-', '', text).strip() )
aW1wb3J0IHJlCnRleHQgPSAnMTIzICEiwqckJSYvKCk9IMOkw7zDtsO8w4TDlsOcw4TDn8Ofw5/DnyBoZWxsby0xMjMsIGhlbGxvLWhlbGxvLCBoZWxsby0uJwpwcmludCggcmUuc3ViKHInLT9cZCstP3xbXlx3IC1dfF98LSg/IVx3KXwoPzwhXHcpLScsICcnLCB0ZXh0KS5zdHJpcCgpICkK