Can you write a short example that we can use to re-create your problems? 
For me, clangd_client does indeed provide the info you are having problems with.
With an example from you, we might be able to either show you how to get the info, or fix the problem.
My os is win7 , clangd.exe is  from latest version LLVM-16.0.5-win64 which  full installed ,compiler is winlibs-x86_64-mcf-seh-gcc-13.1.0-mingw-w64ucrt-11.0.0-r1,no msys . In CB , compiler settings is right  ,  search directories  is right .
My Project to test  clangd_client  is simplest  "hello world" , add several varialbes and simple classes , the program is normally compiling and running . clangd_client can jump to class( I defines myself) declaration and implementation rightly.  But  it  don't  give the right hint of member funtions , and a varialbe of string type it give a hint that is a int type. 
if there is any setting and step I omit please instruct me .
Below is a part  info  of LSP messages 
LSP diagnostics: main.cpp|:|----Time: 15:16:19.218---- (5 diagnostics)|
E:\workspace\testcode\test1\HelloMingw64\main.cpp|1|note:'iostream' file not found|
E:\workspace\testcode\test1\HelloMingw64\main.cpp|8|warning:Using directive refers to implicitly-defined namespace 'std'|
E:\workspace\testcode\test1\HelloMingw64\main.cpp|12|note:Unknown type name 'string'|
E:\workspace\testcode\test1\HelloMingw64\main.cpp|25|note:Use of undeclared identifier 'cout'|
E:\workspace\testcode\test1\HelloMingw64\main.cpp|25|note:Use of undeclared identifier 'endl'|
LSP diagnostics: Test1.h|:|----Time: 15:16:20.533---- (0 diagnostics)|
LSP diagnostics: Test.h|:|----Time: 15:16:21.815---- (0 diagnostics)|
LSP diagnostics: Test.cpp|:|----Time: 15:16:22.844---- (4 diagnostics)|
E:\workspace\testcode\test1\HelloMingw64\src\Test.cpp|2|note:'iostream' file not found|
E:\workspace\testcode\test1\HelloMingw64\src\Test.cpp|4|warning:Using directive refers to implicitly-defined namespace 'std'|
E:\workspace\testcode\test1\HelloMingw64\src\Test.cpp|18|note:Use of undeclared identifier 'cout'|
E:\workspace\testcode\test1\HelloMingw64\src\Test.cpp|18|note:Use of undeclared identifier 'endl'|
LSP diagnostics: main.cpp|:|----Time: 15:19:41.802---- (5 diagnostics)|
E:\workspace\testcode\test1\HelloMingw64\main.cpp|1|note:'iostream' file not found|
E:\workspace\testcode\test1\HelloMingw64\main.cpp|8|warning:Using directive refers to implicitly-defined namespace 'std'|
E:\workspace\testcode\test1\HelloMingw64\main.cpp|12|note:Unknown type name 'string'|
E:\workspace\testcode\test1\HelloMingw64\main.cpp|26|note:Use of undeclared identifier 'cout'|
E:\workspace\testcode\test1\HelloMingw64\main.cpp|26|note:Use of undeclared identifier 'endl'|
LSP diagnostics: main.cpp|:|----Time: 15:19:51.121---- (12 diagnostics)|
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