Laravel crud, update error (Call to a member function update() on null)

So, I’m trying to make update function, using this

 public function editProfile(Request $request, $id)
{
    // Validating
    $request->validate([
        // 'username' => 'nullable|unique:users|min:4',
        // 'email' => 'nullable|unique:users|email:rfc,dns',
        'contact_phone' => 'nullable|digits_between:9,12',
        'bio_en' => 'nullable',
        'bio_ar' => 'nullable',
        'icon' => 'nullable',
        'logo' => 'nullable',
        'plan_id' => 'required',
        'category_id' => 'required',
        'is_local' => 'required',
    ]);
    
    $user = User::find($id);
    $user->update([
        'username' => $request->username,
        'email' => $request->email,
        'contact_phone' => $request->contact_phone,
        'bio_en' => $request->bio_en,
        'bio_ar' => $request->bio_ar,
        'logo' => $request->logo,
        'icon' => $request->icon,
        'plan_id' => $request->plan_id,
        'category_id' => $request->category_id,
        'referred_by_id' => Auth::user()->id,
    ]);



    if ($user) {
        return back()->with("success", __("editedSuccessfully"));
    } else {
        return back()->with('error', __("somethingWentWrongTryAgainLater"));
    }
}

}

but I get the error
Call to a member function update() on null
shows on line $user->update
hope anyone can help me

error show