Hi Antos,
This forum is just a user to user forum, no-one here has any control over decisions Microsoft make and it is unlikely they will ever produce a lighter version of Windows 11.
If your system was originally installed with Windows 8, most likely your hardware is too old to install Windows 11, there are methods provided online to install Windows 11 on unsupported hardware, but honestly, your hardware may not be suitable to try that.
Click your Start Button, then just type msinfo and press Enter, please provide a screenshot of the resulting System Information window.