hashcat Forum

A beginner here on password cracking. So my friend have  a excel file password protected which I am not sure if is 2019 or 2021 office version. He had forgotten the password completely and asked if I could open it somehow. He is ready to buy a new system for it. I see that the latest hashmode on hashcat is only for office 2013 (9600). Does anybody know if it will work for newer excel files? Also if I buy a 4090 GPU, what will be a realistic expectation on cracking the password, say if the password is 8 digits and I need to do a full brute force on it.
I tried Dr.Excel I see Password app on CPU processing, but it was slow. Thanks for your help.

first run office2john.py or (exe) from John the Ripper suite on your file and see whether you can extract a hash from the file or not

if not, the used encryption is not (or not yet) supported and therefore not attackable