A great source for structured, large-scale datasets. You can search for educational text, and use the Kaggle API to automate the download of up to 100k records.
If you tell me this, I can point you to the exact dataset link. Download 100k Education txt
Here are the best methods to handle a request of this scale: A great source for structured, large-scale datasets
What is the specific (e.g., K-12, academic research, programming)? A great source for structured
An open repository of web crawl data. You can filter their petabyte-scale database for educational domains (e.g., .edu) to extract huge volumes of educational text.
For academic and scientific educational content, you can use their OAI-PMH interface to download metadata and abstracts for over 100k papers.