Usually there are backup servers when talking about websites. As long as you pay, it is very difficult for something to delete itself. We are at the limits of the impossible. I would be calm if I were you.
At most, you could think about making a payment investment for the site for 100 years. At least you will be sure that the site stays online for at least 100 years. Among other things, it is also good for search engines. Sites that have payments spanning years are favored by search engines.