Here are a couple of things that may be helpful. First, Safari is installed as part of the Mac's operating system and normally can not be individually updated. There was a recent Safari update to version 15 and that has caused many people serious problems, so I wouldn't install it until a fix is released. As to updating your computer's operating system, if it shows none available, that means that your current OS is now up to date. If you wish to change to a newer operating system, that is called an upgrade, not an update. You can find upgrades in the Apple App store. If you wanted to upgrade your Safari, because of access problems, at this time I would suggest using another browser such as Firefox or Chrome.