Will my e-mail address get freed up after account deletion?

No, the address will not be freed up again after you remove it from your account or delete your account.

If you actually want to keep the address, consider adding an alias to your account and start using that. You can create an Inbox Rule to move emails from your original address to another folder or even delete it. Once the amount of junk for the address reduces again and consider actively using it again, you could remove the rule.

Note that there is a difference between closing/deleting your account and creating a new one, and adding and removing aliases (email addresses) to your existing account.

See; Close your Outlook.com account - Microsoft Support
And; Add or remove an email alias in Outlook.com - Microsoft Support

In both articles, you'll also find the confirmation that the email address will be lost for good when you remove the alias from your Microsoft Account or delete your Microsoft Account entirely.