It’s generally fine to delay iOS updates for a week or two, but it’s probably a good idea to get the latest version, iOS 14.4.2, as soon as possible. It fixes a security flaw that Apple says may have been exploited in the wild (via MacRumorsThe update also applies to iPadOS, so take a few minutes to go to Settings> General> Software Update.
According to Apple’s update notes, the security flaw enabled universal cross-site scripting. In other words, a malicious website or script could access information from other web pages you’ve opened, which isn’t great, especially since Apple says some sites may do this.
As I mentioned in January when Apple released a similar update, it doesn’t mean it’s time to completely lock your phone and treat it as if it were radioactive until you can update it. Stay away from sketchy websites (which is good advice in general) and update your phone sooner rather than later.