It's best to wash strawberries right before you plan to eat them, not before refrigerating. Washing them beforehand can lead to mold and mushy berries.
Strawberries are highly susceptible to absorbing moisture. When you wash them, they soak up water. If you then refrigerate them, that excess moisture creates a perfect environment for mold to grow and causes the berries to become soft and mushy much faster. Instead, store unwashed strawberries in their original container (or a breathable container) in the refrigerator. When you're ready to enjoy them, give them a gentle rinse under cool water and pat them dry with a paper towel. This ensures they stay fresh and flavorful for as long as possible.
If you absolutely must wash your strawberries ahead of time, make sure to dry them thoroughly. Use a salad spinner or gently pat them dry with multiple layers of paper towels. Store them in a container lined with paper towels to absorb any remaining moisture. However, keep in mind that even with thorough drying, they won't last as long as unwashed berries.