It's better to use different language, like saying how we're exceedingly confident that the earth is round, rather than it being an absolute. Sort of like our confidence asymptotically approaches absolute but never actually reaches it.

This is similar to Hume's argument for our belief that the sun will rise tomorrow. Obviously, we all believe (even flat-earthers) that the sun will rise tomorrow and we have much science to indicate this will continue to be the case for a long time. Still, that doesn't mean we can be 100% confident this is the case. It's frankly just exceedingly difficult to be 100% absolutely sure about anything, unless it's first order mathematics.