I could go either way on OS and open to other suggestions. I prefer Apple hardware but don’t have the budget and need a new machine.
I got my Asus Zen book UX425 (MX450 + R5 5500u) for $399
Definitely don’t get a Chromebook, they’re a waste of money, and they’re cheap useless garbage.
The Ideapad 3 by Lenovo is often priced at $499. So, I think picking one up soon at $450 will be easy to find.
Lenovo Flex Chromebook seems to be a good one. Acer has 3 tiers. So, if you look the 300 or 500 or 700 you will see some good choices. I think their Spin 500 or 700 are especially good.
If you’re going to spend $400, you might as well get a fully-functional Windows laptop. Chromebooks are basically laptops for G Suite (e.g. Gmail, Google Docs, YouTube, etc.).
Fortunately Black Friday and Cyber Monday are around the corner (if you live in 'Murica) so there will be no shortage of feature-rich laptops for the same price (or cheaper).