看到我的评论，改变了我的设置，现在它的工作：（好吧，它不再是一个单一的条目，但嘿：-）
项目文件夹：

Plugin folder
|-- [src]
|   |-- [block1]
|   |   |-- block1.js
|   |   |-- style.scss
|   |   `-- editor.scss
|   |-- [block2]
|   |   |-- block2.js
|   |   |-- style.scss
|   |   `-- editor.scss
|   `-- index.js
|   `-- css.js
`-- [build]
    |-- index.js
    |-- style.build.css
    `-- editor.build.css

在css.js中：

import './block1/style.scss'
import './block1/editor.scss'
import './block2/style.scss'
import './block2/editor.scss'

在webpack.config.js中：

const defaultConfig = require("./node_modules/@wordpress/scripts/config/webpack.config");
const MiniCssExtractPlugin = require('mini-css-extract-plugin');

module.exports = {
    ...defaultConfig,
    entry: {
        index: path.resolve( process.cwd(), 'src', 'index.js' ),
        css: path.resolve( process.cwd(), 'src', 'css.js' ),
    },
    optimization: {
        ...defaultConfig.optimization,
        splitChunks: {
            cacheGroups: {
                style: {
                    name: 'style',
                    test: /style\.s?css$/,
                    chunks: 'all',
                    enforce: true,
                },
                editor: {
                    name: 'editor',
                    test: /editor\.s?css$/,
                    chunks: 'all',
                    enforce: true,
                },
            },
        },
    },
    plugins: [
        ...defaultConfig.plugins,
        new MiniCssExtractPlugin({
            filename: 'blocks.[name].build.css'
            }),
    ],
    module: {
        ...defaultConfig.module,
        rules: [
            ...defaultConfig.module.rules,
            {
                test: /\.s?css$/,
                exclude: /node_modules/,
                use: [
                    MiniCssExtractPlugin.loader,
                    'css-loader',
                    'postcss-loader',
                    'sass-loader'
                ],
            },

        ]
    },
};

输出生成文件夹：

[build]
|-- blocks.editor.build.css
|-- index.js
|-- blocks.style.build.css
|-- style.js (ignore)
|-- editor.js (ignore)
|-- css.js (ignore)
`-- (...and indentical map files)

实际上，您不需要多个条目。使用当前解决方案中的配置，您只缺少一个选项来使其按您希望的方式工作。filename选项必须在块名称的基础上动态设置。

plugins: [
    new MiniCssExtractPlugin({
      filename: ({ chunk }) => `${chunk.name.replace('/js/', '/css/')}.css`,
    })
],

这将为每个块创建一个.css文件。由于您已经有了style和editor块，它将创建style.css和“editor.css”，每个块都有相应的css或scss导入到js文件中。
检查文件
它看起来像这样，唯一的增加是filename对MiniCssExtractPlugin选项的更改，以及css条目的删除。

module.exports = {
    ...defaultConfig,
    entry: {
        index: path.resolve( process.cwd(), 'src', 'index.js' ),
    },
    optimization: {
        ...defaultConfig.optimization,
        splitChunks: {
            cacheGroups: {
                style: {
                    name: 'style',
                    test: /style\.s?css$/,
                    chunks: 'all',
                    enforce: true,
                },
                editor: {
                    name: 'editor',
                    test: /editor\.s?css$/,
                    chunks: 'all',
                    enforce: true,
                },
            },
        },
    },
    plugins: [
        ...defaultConfig.plugins,
        new MiniCssExtractPlugin({
          filename: ({ chunk }) => `${chunk.name.replace('/js/', '/css/')}.css`,
          // chunkFilename: "[name].css"
        })
    ],
    module: {
        ...defaultConfig.module,
        rules: [
            ...defaultConfig.module.rules,
            {
                test: /\.s?css$/,
                exclude: /node_modules/,
                use: [
                    MiniCssExtractPlugin.loader,
                    'css-loader',
                    'postcss-loader',
                    'sass-loader'
                ],
            },

        ]
    },
};

应用发布的答案，我设计了一个配置，允许包scss文件共享相同的名称，并将它们分组在<name>.css中，其余的分组在styles.css中。
我在配置文件的开头定义了一个数组，其中包含所有CSS块名称组。

const chucksCSS = ['style', 'editor'];

在Bornie和Raba帖子中，我定义了一个新条目，允许使用名称“main”作为块名。

module.exports = {
...defaultConfig,
  entry: {
    index: './src/index.jsx',
  },
...defaultConfig,
}

每个CSS群组的属性都会在cacheGroups设定中解构。

...
optimization: {
    splitChunks: {
      cacheGroups: {
        ...chucksCSS.map((name) => ({
          name,
          test: new RegExp(`${name}\\.s?css$`),
          chunks: 'all',
          enforce: true,
        })).reduce((acc, current) => {
          acc[current.name] = current;
          return acc;
        }, {}),
      },
    },
  },
...

要完成添加插件MiniCssExtractPlugin和配置filename以分配块名称，并将默认块名称重命名为style，例如以指定的名称生成文件。

plugins: [
    ...
    new MiniCssExtractPlugin({
      // Chunk name 'index' is set by entry point where is not recognized by any cacheGroup
      filename: ({ chunk }) => `${chunk.name === 'index' ? 'styles' : chunk.name}.css`,
    }),
    ...
],

它看起来像这样

const chucksCSS = ['style', 'editor'];

module.exports = {
    ...defaultConfig,
    entry: {
        index: './src/index.jsx',
    },
    optimization: {
        ...defaultConfig.optimization,
        splitChunks: {
            cacheGroups: {
                ...chucksCSS.map((name) => ({
                     name,
                    test: new RegExp(`${name}\\.s?css$`),
                    chunks: 'all',
                    enforce: true,
                })).reduce((acc, current) => {
                  acc[current.name] = current;
                  return acc;
                }, {}),
            },
        },
    },
    plugins: [
        ...defaultConfig.plugins,
        new MiniCssExtractPlugin({
          // Chunk name 'index' is set by entry point where is not recognized by any cacheGroup
          filename: ({ chunk }) => `${chunk.name === 'index' ? 'styles' : chunk.name}.css`,
        })
    ],
    module: {
        ...defaultConfig.module,
        rules: [
            ...defaultConfig.module.rules,
            {
                test: /\.s?css$/,
                exclude: /node_modules/,
                use: [
                    MiniCssExtractPlugin.loader,
                    'css-loader',
                    'postcss-loader',
                    'sass-loader'
                ],
            },

        ]
    },
};