The 8GB Duet 5 seems like a good choice for your son's high school needs. It has a long battery life, a powerful SoC, and a comfortable keyboard. The device features a 1080p display and a durable magnetic keyboard with a strong stand. Some models even come with a pen holder (without the pen). It can be used as both a tablet and a laptop. With updates supported until 2030, it will last for a long time. The 8GB of RAM and the Snapdragon 7c Gen 2 ensure a smooth and responsive experience, unlike other chromebooks. However, if you opt for the 4GB model, multitasking may be limited. I did notice an issue with Bluetooth causing the tablet to restart when used with certain headphones (not all). Alternatively, you could consider the Duet 3, which is similar but smaller and has 4GB of RAM. But the 8GB RAM model costs $475 on Amazon which is close to the $500 budget. But for writing the 4GB model seems great