Wordpress can also be installed on your own webspace, then you can freely choose the domain yourself. However, you need a homepage package with a database, php, etc., and of course the necessary knowledge. In addition, you are responsible for security updates, spam protection, etc., which is usually the biggest problem when the site becomes somewhat more popular. Alternatively, you can also redirect a cheap starter domain package to another webspace to have your own domain name. (kosan.de redirect to e.g. wordpress.kosan.de) To my knowledge, you can often configure it in such a way that the original domain remains in the browser even after the redirect.