Too much in HYSA vs investments?

32M, here is what my savings currently look like:

HYSA: $400K Checking: $10K Wealthfront Investment Account: $165K IRA: $27K 401k: $225K Other stocks: $8K No debt

Other info: Due to a company policy, the majority of my 401K contributions are returned to me at the end of the year. I still get to keep the company match and a little bit of my funds in there, but due to that policy I’m not able to grow the balance much beyond where it is now. I’ve been making my IRA contribution each year with this returned amount, and the rest has either gone into the HYSA or the Wealthfront account. I am saving about $7-8K a month and contributing $2.5K of that to the Wealthfront account, the rest goes to the HYSA. I don’t have plans to make any major purchases in the next few years.

Should I be investing more? If so, should it just go into Wealthfront, or are there better ways to diversify it? Thanks!