maybe it works.

src/main/java/band/kessokuteatime/nightautoconfig/config/ExampleConfig.java

@@ -0,0 +1,13 @@
+package band.kessokuteatime.nightautoconfig.config;
+
+import me.shedaniel.autoconfig.ConfigData;
+import me.shedaniel.autoconfig.annotation.Config;
+
+@Config(name = "example")
+public class ExampleConfig implements ConfigData {
+    public int exampleInt = 10;
+    public double exampleDouble = 3.14159;
+    public float exampleFloat = 2.71828F;
+    public boolean exampleBoolean = true;
+    public String exampleString = "Hello, World!";
+}

src/main/java/band/kessokuteatime/nightautoconfig/serializer/ConfigType.java

@@ -0,0 +1,24 @@
+package band.kessokuteatime.nightautoconfig.serializer;
+
+import me.shedaniel.autoconfig.annotation.Config;
+import me.shedaniel.autoconfig.util.Utils;
+
+import java.nio.file.Path;
+
+public enum ConfigType {
+    JSON("json"), YAML("yaml"), TOML("toml"), HOCON("conf");
+
+    private final String suffix;
+
+    ConfigType(String suffix) {
+        this.suffix = suffix;
+    }
+
+    public String suffix() {
+        return suffix;
+    }
+
+    public Path getConfigPath(Config definition) {
+        return Utils.getConfigFolder().resolve(definition.name() + suffix());
+    }
+}

src/main/java/band/kessokuteatime/nightautoconfig/serializer/NightConfigSerializer.java

@@ -0,0 +1,52 @@
+package band.kessokuteatime.nightautoconfig.serializer;
+
+import com.electronwill.nightconfig.core.conversion.ObjectConverter;
+import com.electronwill.nightconfig.core.file.CommentedFileConfig;
+import com.electronwill.nightconfig.core.file.CommentedFileConfigBuilder;
+import me.shedaniel.autoconfig.ConfigData;
+import me.shedaniel.autoconfig.annotation.Config;
+import me.shedaniel.autoconfig.serializer.ConfigSerializer;
+import me.shedaniel.autoconfig.util.Utils;
+
+import java.util.function.UnaryOperator;
+
+public class NightConfigSerializer<T extends ConfigData> implements ConfigSerializer<T> {
+    protected final Config definition;
+    protected final Class<T> configClass;
+    protected final ConfigType type;
+    protected final CommentedFileConfigBuilder builder;
+
+    public NightConfigSerializer(Config definition, Class<T> configClass, ConfigType type, CommentedFileConfigBuilder builder) {
+        this.definition = definition;
+        this.configClass = configClass;
+        this.type = type;
+        this.builder = builder;
+    }
+
+    public NightConfigSerializer(Config definition, Class<T> configClass, ConfigType type, UnaryOperator<CommentedFileConfigBuilder> builder) {
+        this(definition, configClass, type, builder.apply(CommentedFileConfig.builder(type.getConfigPath(definition))));
+    }
+
+    public NightConfigSerializer(Config definition, Class<T> configClass, ConfigType type) {
+        this(definition, configClass, type, UnaryOperator.identity());
+    }
+
+    @Override
+    public void serialize(T t) throws SerializationException {
+        CommentedFileConfig config = new ObjectConverter().toConfig(t, builder::build);
+        config.save();
+        config.close();
+    }
+
+    @Override
+    public T deserialize() throws SerializationException {
+        CommentedFileConfig config = builder.build();
+        config.load();
+        return new ObjectConverter().toObject(config, this::createDefault);
+    }
+
+    @Override
+    public T createDefault() {
+        return Utils.constructUnsafely(configClass);
+    }
+}