How do I change the height of GridView? – Flutter

I am currently displaying two rows of widgets in a GridView.

However, I am unable to limit the height and narrow the spacing.
I would like to eliminate the extra gap.

I want to eliminate the red butts.
I would like to eliminate this area and display the widget at the bottom higher.

But I could not do it. So I hope you can help me.

 Expanded(
              child: Padding(
                padding: const EdgeInsets.all(8.0),
                child: GridView.count(
                  crossAxisCount: 2,
                  shrinkWrap: true,
                  mainAxisSpacing: 0,
                  crossAxisSpacing: 30,

                  children: [
                    //一つ目
                    Visibility(
                      visible: numberOfFeatures >= 3,
                      child: Column(
                        children: [
                          TextField(
                            decoration: InputDecoration(hintText: "ONE"),
                            onChanged: (value) {
                              setState(() {
                                _slider1Text = value;
                                features[0] = _slider1Text;
                              });
                            },
                          ),
                          Slider(
                              min: 0,
                              max: 35,
                              divisions: 15,
                              value: _slider1Value.toDouble(),
                              onChanged: _change1Slider),
                        ],
                      ),
                    ),
                    //二つ目
                    Visibility(
                      visible: numberOfFeatures >= 3,
                      child: Column(
                        children: [
                          TextField(
                            decoration: InputDecoration(hintText: "TWO"),
                            onChanged: (value) {
                              setState(() {
                                _slider2Text = value;
                                features[1] = _slider2Text;
                              });
                            },
                          ),
                          Slider(
                              min: 0,
                              max: 35,
                              divisions: 15,
                              value: _slider2Value.toDouble(),
                              onChanged: _change2Slider),
                        ],
                      ),
                    ),
                    //三つ目
                    Visibility(
                      visible: numberOfFeatures >= 3,
                      child: Column(
                        children: [
                          TextField(
                            decoration: InputDecoration(hintText: "THREE"),
                            onChanged: (value) {
                              setState(() {
                                _slider3Text = value;
                                features[2] = _slider3Text;
                              });
                            },
                          ),
                          Slider(
                              min: 0,
                              max: 35,
                              divisions: 15,
                              value: _slider3Value.toDouble(),
                              onChanged: _change3Slider),
                        ],
                      ),
                    ),

                    //4つ目
                    Visibility(
                      visible: numberOfFeatures >= 4,
                      child: ListTile(
                        title: TextField(
                          onChanged: (value) {
                            setState(() {
                              _slider4Text = value;
                              features[3] = _slider4Text;
                            });
                          },
                        ),
                        subtitle: Slider(
                            min: 0,
                            max: 35,
                            divisions: 15,
                            value: _slider3Value.toDouble(),
                            onChanged: _change4Slider),
                      ),
                    ),
                  ],
                  // if (numberOfFeatures >= 4) ...[TextField(), Text('ちんう')],
                  // if (numberOfFeatures >= 5) TextField(),
                  // if (numberOfFeatures >= 6) TextField(),
                  // if (numberOfFeatures >= 7) TextField(),
                  // if (numberOfFeatures >= 8) TextField(),
                ),
              ),
            ),