Our human brains tend to get confused by the gap between signifier and signified, mistaking (as Plato and so many others have done) a vague abstraction (the word) with a necessarily existing phenomenon (the concept made “real”). As you say, there’s always a huge gap. That said, there’s a big difference between beliefs based on empirical observation and beliefs based on our desire for simplistic stories that meet our need for “meaning.” There really is a universe out there and when different people with different beliefs make certain measurements, those measurements remain consistent regardless of culture, beliefs, or time at which the measurements are made. This is why we can acquire knowledge about the real world and not remain trapped in a mental Disneyland in which “everything is as true as everything else.” Our words don’t do a very good job of describing reality but fortunately mathematics does a more adequate (though still imperfect) job. For each task, the tools must be suitable. We don’t need perfect descriptions; “good enough” is usually more than good enough. This is why empirical science has flourished while philosophy has become for the most part a stagnant backwater.