While the background radiation levels aren’t exceptionally dangerous and people do live in the exclusion zone, there are a large number of radioactive hotspots that could be extremely dangerous. They’re small pieces of the reactor core that were spread around by the explosion, and they’re extremely radioactive still. If you inhaled one or if you were to eat a plant or animal that had eaten/absorbed one it could do a significant amount of damage to you. Kyle Hill has some really good videos on this topic.