If you’re running a website that has a high traffic, querying posts on each load will not be efficient. You should instead cache the data. Now, I’m not talking about a plugin that caches the pages, I’m talking about caching your query.
You can run 10 queries and fetch 10 post IDs from each category, and then form an array of post IDs and store them in the database, using a transient. This way, you can fetch the transient data and directly run a loop and output the post data.