Why am I getting so much more spam than just two weeks ago? At least 10x as much.

It's not just you. These things come in waves.

If you want a temporary email address for use with goods or services that are likely to sell it to others, consider using an alias: Add and manage email aliases for iCloud Mail on iCloud.com. When it becomes clogged with spam delete it.

You can't turn off spam unless you ditch the email address the spam is being sent too. Over the years, you have used this email address for online activity and it has found its way onto the dark net where it is sold and resold to spammers. There are spam campaigns that increase at certain times of the year too.

You can manage some of this spam with a product like SpamSieve. I am not on their payroll…

Do not reply to spam, or attempt to cancel it via their fake unsubscribe link that just confirms it is a valid email target.

I don' use SpamSieve myself, as I resort to other means. Try to install SpamSieve per the vendor's instructions and confer with them if you have issues.