I am no expert on computers, but my personal opinion is;
Each new version of operating system is intended to be more secure from hackers and malicious outsiders.
A. Before considering the upgrade, verify whether your computer will run Win11 satisfactorily. Microsoft doesn't guarantee this before it orders you to upgrade.
B. Alternatively:- If you don't use your computer for critical stuff such as banking, you are not at much risk from hackers. After all, if uou only use it for emails and casual websearches, the worst they can steal from your computer, is your contact list (& their details). Or they can block your access to your hard disk and blackmail you for a password to release it back to you.
Ideally, you should always run the latest version of software, on the latest computer, and keep it updated.