To make it short: to reset the windows to factory settings: Edit>Preferences>Window management>Reset saved window positions to default values
Otherwise, you are missing a dialog that can be re-shown using "Windows>Dockable dialogs>Tool options".
Reinstalling Gimp is rarely useful. It keeps all the setting in your Gimp profile and the re-installed instance finds and uses your old profile, so you are back to square one.
PS: It's better to do a screen capture instead of taking a photo of your screen. No perspective distortion, no moiré, actual colors, etc... This gives us a lot more clues as to what can be wrong.
Otherwise, you are missing a dialog that can be re-shown using "Windows>Dockable dialogs>Tool options".
Reinstalling Gimp is rarely useful. It keeps all the setting in your Gimp profile and the re-installed instance finds and uses your old profile, so you are back to square one.
PS: It's better to do a screen capture instead of taking a photo of your screen. No perspective distortion, no moiré, actual colors, etc... This gives us a lot more clues as to what can be wrong.