This is what you came for. How to actually tunnel out of the school network.

Educational institutions implement web filters and administrative restrictions on Chromebooks to ensure a safe learning environment, protect students from harmful content, and comply with various educational regulations. If a website is blocked and it is needed for schoolwork, the most effective and appropriate steps to take are:

While various methods exist to bypass these restrictions, it is important to remember that such actions often violate school Acceptable Use Policies (AUP) and can lead to disciplinary consequences. Common Methods to Unblock Websites