I've accidentally stumbled upon the --no-compiler-signature directive that you can use to make your generated Delphi executable slightly smaller.
Add it to the "Additional options to pass to the compiler" in project options -> Building -> Delphi Compiler -> Compiling node, and not only can your generated file reduce a little bit in size, it can also remove the string "Embarcadero Delphi for Win64 compiler version" away from the generated file.
Learn the command line used to compile System.pas in Delphi