This is the hardest pill to swallow. If the password is a random 20-character string generated by LastPass, or if the original creator is dead, the data is gone. Permanently. This is the purpose of encryption: to make data unrecoverable without the key. Delete the archive to free up space. Consider this a lesson in modern password management.
If you are simply looking for the password because you downloaded the file from a specific website: winrar password unlock
These tools can be effective in unlocking WinRAR passwords, but they may require significant computational resources and time. This is the hardest pill to swallow
: Test variations of passwords you frequently use for other accounts. winrar password unlock