How to access Project Name and compile Date/Time as variables within the code?

As the documentation shows, you can inject the Unix time into the build system by writing

build_flags =
   -D CURRENT_TIME=$UNIX_TIME

You can use this timestamp to convert it into a human readable time.

Alternatively and way more easier, use the __DATE__ and __TIME__ built-in macros that are compiler-defined and are already strings (https://www.cprogramming.com/reference/preprocessor/DATE.html).

While the project name isn’t directly available, you can pass in $PROJECT_DIR (string escaped) to get the full ptath to the projects, e.g., C:\Users\Max\temp\atmega4809.