I did it this way: https://github.com/generate94/convert_dll_to_lib/blob/main/README.md (includes an executable along w the source code)

basically:

Extract Exports – Run dumpbin /EXPORTS on the DLL to list exports.

Create .def – Write LIBRARY <DLL_NAME> and EXPORTS header.

Generate .lib – Use lib.exe /DEF:<def file> /OUT:<lib file>