I'm looking for the C build settings but it seems I have to add my settings through Makefile. Why we don't have visual Build Settings for the C complier in 2022 like in other eclipse based tools?
A ModusToolbox application is not "Eclipse based" -- it is Make based. You can use command line, VS Code, IAR, or uVision in addition to Eclipse. Some users even use their own internal tools.
In Eclipse, if you right-click on the main project (e.g., Hello_World) and select "Properties", there are many Eclipse settings including C/C++ Build and C/C++ General.
What types of settings are you looking for? Are they being ignored?
I know that we must manually edit MAKEFILE, but it is more complicated to maintain in consistent with IDE (for example DEFINES must be also filled in C/C++ General -> Paths and Symbols to show / hide correct code using #ifdef) https://community.infineon.com/t5/PSoC-6/Modus-Toolbox-C-C-Build-Settings/m-p/353656#M13060
I also would like appreciate to integrate more options and revert back Tool Settings, which was removed from 2.4.0
And regarding Optimisation levels - it did not work for me as Modus toolbox override CYFLAGS= -Os or -O0 in Debug CONFIG. So I must create CONFIG=Custom but it leads to more editing related to this config and make additional settings on Startup tab for this configuration especially to generate HEX in correct folder.
It will be nice if it will be more user friendly.