Help Needed: Strawberry plants not fully ripening

Hello!I have 5 strawberry plants planted on my balcony. They are all producing fruits, but they are very small and don't fully ripen. As you can see in the first photo, the tip always remains white and has dark spots.Should I wait longer or am I missing something? I add fertilizer every two weeks and water regularly without saturating the substrate.Thanks!https://preview.redd.it/oowlw88jgy4b1.jpg?width=2016&format=pjpg&auto=webp&v=enabled&s=69b07a90f99f28d152b73d59bf22d456d48c9650https://preview.redd.it/oihtnk8jgy4b1.jpg?width=4480&format=pjpg&auto=webp&v=enabled&s=831ed3c8ecbd87c44428b6e1fa5bdf8ef0770ef7​