Best way to invest money for the next 5-6 years

Hi all,

I'm NOT a US-citizen but currently staying and working in the US. My working visa can be extended up to 6 years, I haven't decided what to do after that but want to save money until then.

Currently, I save about $2k every month and having about 20k in my checking account, also have some VOO and QQQ shares in Robinhood but not much. I know just keeping money in checking account is not smart and looking for advice on how to do better. I see so many options for saving accounts like HYSA, CD, or market mutual funds, which I don't really understand much after reading about them so looking to reddit for help. Right now, which would be the best choice? If so, how to choose which bank to open an account with?

Thanks everyone!