HD44780 Text Display

Do you have a toolchain installed? And make sure at the end of the installation it is added to the the search path. Then the cmake search for Toolchain should work.
It is also possible to add toolchains manually to the config file, it is documented somewhere in the VSCode cmake extensions.

Yes, there was a problem with the toolchain path. I guessed something like this.
I use Win 11 machine under user priveleges for security reasons. I installed and reinstalled arm toolchain both under user with elevation and admin accounts. The checkbox “add to path” was active. Yet it added the path only for admin environment, not to system one. So under user acc it was not visible. This is rather the toolchain installer misbehavior.

So you can check and modify the cmake-tools-kits.json file manually, my windows installation has it here:
c:\Users\super\AppData\Local\CMakeTools\cmake-tools-kits.json

And here is some information about this file:
https://vector-of-bool.github.io/docs/vscode-cmake-tools/kits.html

Hello again.
Bless, no more problems in the project for now. But, how can I upload the code to my board? No upload button. cmake-variants.yaml has these settings:

board:
default: NUCLEO_F303RE
choices:
NUCLEO_F303RE:
short: NUCLEO_F303RE
settings:
MBED_TARGET: NUCLEO_F303RE

    UPLOAD_METHOD: MBED

Ahoj,

according to guide you have to choose one of possible uload methods from the list. In case of your dev board i recommend to use STM32CubeCLT. As soon as you will have installed this, then you can change settings in your cmake-variants.yaml

UPLOAD_METHOD: MBED

to

UPLOAD_METHOD: STM32CUBE

And in VS Code CMake change the build settings from ALL to flash-main (in your case probably flash-HelloWorld)

BR, Jan