Use Home Account
This kajig might not work for most people, but it lets you sign into a second user that is separate from your main school account. You can access any website and download/use any extensions on your secondary home account. To do this kajig you need to be able to add other accounts on the sign-in screen and secondary accounts needs to be enabled. Follow these steps:
If you're already signed in, sign out of your profile and sign into your other acc (home or school, make sure you're signed in with each one)
Once you're signed into both accounts on your chromebook, sign into your school acc (sign out if you're on your home acc)
Press the time on the shelf
Press your profile picture on the top-left of the menu
Press "Sign in with other accounts"
Sign into your home account
Now you can easily switch users from your school to home account using ctrl + alt + , (comma) or ctrl + alt + . (period)
If you sign out you can sign into your home account as a secondary profile again starting from step 2. NOTE: you can't use android apps or linux apps on your secondary profile, but you can move the window onto your secondary profile from your school one