Unable to include rapidjson in my C++ project

So i have a project directory structure as below

Application
-Utils
 -Transport
  -include
   -Foo.h
  -src
   Foo.cpp
   CMakelists.txt(a)
 -CMakeLists.txt(b)
-third_party
 -argparse
 -rapidjson ( new added)
  -bin
  -include
  ...
  -CMakeLists.txt
 -CMakeLists.txt(c)

CMakelists.txt(a) looks like below

add_library(${PROJECT_NAME}
    Foo.cpp
)

target_include_directories(${PROJECT_NAME}
    PUBLIC
    $<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/include>
    $<INSTALL_INTERFACE:${CMAKE_INSTALL_INCLUDEDIR}>
)

target_link_libraries(${PROJECT_NAME}
    PUBLIC
    ...
    CURL::libcurl
    RapidJSON <--newly added
)

CMakelists.txt(b) looks like

project(Transport LANGUAGES CXX)

add_subdirectory("src")

and CMakelists.txt(c) looks like below

add_subdirectory(argparse)
add_subdirectory(rapidjson) <--newly added

Plesae note that my application was compiling before i added rapidjson but since there was a necessity to add rapidjson, i added it and since rapidjson is also a header only library like argparse, i copied it under the third-party folder , added the subdirectory for rapidjson and than added a link dependency on RapidJSON. But when i try to include

#include "rapidjson/document.h"

in Foo.cpp i get the error

fatal error: 'rapidjson/document.h' file not found
    1 | #include "rapidjson/document.h"
      |          ^~~~~~~~~~~~~~~~~~~~~~

Is my understanding correct that since rapidjson is header only library , its CMakelist.txt will create an interface target RapidJSON that i can include in other targets of my project that require rapidjson and since as per https://github.com/Tencent/rapidjson/blob/v1.1.0/CMakeLists.txt#L107 include_directories(${CMAKE_CURRENT_SOURCE_DIR}/include) than #include "rapidjson/document.h" seems correct to me.

Please note that although i do not think it is necessary but i did tried to include find_package(RapidJSON) in the root CMakelists.txt to see whether that will fix this issue but gives error

CMake Error at cmake-build-debug/third_party/rapidjson/RapidJSONConfig.cmake:3 (include):
  include could not find requested file:

Any pointers on what i am missing here or what assumption are incorrect would be greatly appreciated.

---Update Minimal Reproducible example---

project structure

minimal
-thirdparty
 -argparse ( downloaded files from https://github.com/p-ranav/argparse)
 -rapidjson( downloaded files from https://github.com/Tencent/rapidjson/)
 -CMakelists.txt(a)
-main.cpp
-CMakelists.txt(b)

CMakelists.txt(a)

add_subdirectory(argparse)
add_subdirectory(rapidjson)

CMakelists.txt(b)

cmake_minimum_required(VERSION 3.27)
project(minimal)

add_subdirectory(third_party)

set(CMAKE_CXX_STANDARD 17)

add_executable(minimal main.cpp)

target_link_libraries(minimal
    PUBLIC
    argparse
    RapidJSON
)

main.cpp

#include <iostream>
#include <argparse/argparse.hpp>
#include "rapidjson/document.h"

int main() {
    std::cout << "Hello, World!" << std::endl;
    return 0;
}

error

/Users/foo/CLionProjects/minimal/main.cpp:3:10: fatal error: 'rapidjson/document.h' file not found
    3 | #include "rapidjson/document.h"
      |          ^~~~~~~~~~~~~~~~~~~~~~
1 error generated.

Both argparse and rapidjson are header only libs but seems like for some reason when i include CMakelists.txt from argparse, it is able to find the files but that is not the case for rapidjson.

RapidJSON lists include directories only for install interface. You can add build interface includes yourself as needed:

add_subdirectory(rapidjson)
target_include_directories(RapidJSON SYSTEM INTERFACE $<BUILD_INTERFACE:${CMAKE_CURRENT_LIST_DIR}/rapidjson/include>)

---

Alternatively, as per the documentation you can simply copy the include directory of the library to your project's source tree:

RapidJSON is a header-only C++ library. Just copy the include/rapidjson folder to system or project's include path.