I found the answer here: https://github.com/microsoft/TypeScript/issues/36444#issuecomment-578572999

I have to convert my class to type in order to achieve the solution. Something like this:

type PopulationDto<E> = {
    [K in keyof E]: {
        path: keyof E;
        population?: PopulationDto<
            E[K] extends Array<any>
                ? E[K][number]
                : E[K] extends object
                  ? E[K]
                  : any
        >[];
    }
}[keyof E];