Hi,
If the Layout option is no longer available in Start settings, that usually means the redesigned Start menu is already applied. In this version, the All apps section is shown directly on the main panel instead of being tucked away. You can switch its layout between List, Grid, or the default Category view. Could you let me know if that matches what you’re currently seeing? You may refer to this page to see how it’s supposed to appear and get a better idea of how it functions.
Disclaimer: This is a non-Microsoft site. The information seems reliable, but be careful with ads. Research any product before downloading.