React Native: Typescript - data possibly undefined

I've got a some data being fetched using RTK Query. I load this data (array of objects) in a screen and then slice some portion of it.

It's more of a typescript question but I'll post the apiSlice:

interface Post {  userId: number;  id: number;  title: string;  body: string;}export const blogpostsApi = createApi({  reducerPath: 'blogpostsApi',  baseQuery: fetchBaseQuery({ baseUrl: 'http://localhost:3500' }),  endpoints: builder => ({    getBlogPosts: builder.query<Post[], void>({      query: () => '/todos',      transformResponse: (res: Post[], meta) => res.sort((a, b) => b.id - a.id),    }),  }),});

The relevant excerpts from the screen:

const { data, isLoading } = useGetBlogPostsQuery();const latestData = data?.slice(0, 10);useEffect(() => {    if (!isLoading && latestData.length > 0 && some_other_condition) {    ... some code    }}, [latestData]);useEffect(() => {    if (!isLoading && latestData[0].id === 'something'&& some_other_condition) {    ... some code    }}, [latestData]);

As you can see, I've added the optional chaining operator to data?.slice... (as this is a recommended solution for that on SO, from what I have seen. But then typescript also underlines all the instances of latestData.length and latestData[0].id.

Now I know I could silence the typescript error by adding the optional chaining operator to all those instances as well but I'm wondering it that's really the best way of doing it for 2 reasons:

1. Adding it to all the instances will unnecessarily increase the compiled code length
2. The way I use latestData above in the two effects is in conditional statements to check if it exists/is defined so it is perfectly OK for it to be undefined.

So I guess my question is what would be the correct way to solve this error. Isn't adding the optional chaining operator just a quick and dirty hack to silence the error especially if it appears in conditional statements? I know I could also suppress the error by asking Webstorm to ignore it (as per the error screenshot below)
The error: