Access to proccess.env<variable> in spfx

My general aim is to use process.env<variableName> during build locally during development and in devops pipleines during deployment to inject some secrets and passwords. My story about this is pretty same as here (i'm not the author) so I tried every link touching this subject.

What I learned is:
in gulpfile none of plugins folowing this is truthy in condition plugin instanceof webpack.DefinePlugin thus new instance of DefinePlugin is pushed which yields to error:

[08:22:42] Error - [webpack] TypeError: Cannot read properties of undefined (reading 'get')
[08:22:42] Error - 'webpack' sub task errored after 136 ms
Cannot read properties of undefined (reading 'get')
[08:22:42] 'bundle' errored after 9.47 s

When I manually change plugins array adding in gulpfile (code is simplified)

 let pluginDefine = cfg?.plugins?.[1];

    const currentEnv = getClientEnvironment().stringified;
      pluginDefine.definitions = {
        ...pluginDefine.definitions,
        ...currentEnv,
      };

where getClientEnvironment().stringified is:

SPFX_COMPUTER_VISION_ENDPOINT: '"SPFX_COMPUTER_VISION_ENDPOINT"',
SPFX_COMPUTER_VISION_KEY: '"SPFX_COMPUTER_VISION_KEY"'

My console.log(process.env.SPFX_COMPUTER_VISION_KEY) is undefined in any tsx file.

The only variable defined in DefinePlugin I can access is DEBUG.

I even started to edit node_modules@microsoft\spfx-heft-plugins\lib\plugins\webpackConfigurationPlugin\WebpackConfigurationGenerator.js where in DefinPlugin argument I added my variables which still gives undefined.

How can I inject my variables to process.env and use them during build?

Additional environment details

• browser version: Version 122.0.2365.80 (Official build) (64-bit)
• SPFx version: 1.17.4
• Node.js version: 16.18.1
• React version: 17.0.1
• TypeScript version: 4.5.5