Should I invest lump sum or DCA with $20k?

I'll say "lump-sum" but instead of $20k, u can split into 2 or 3 different times. Make sure the $20k is invested into not just one stock, but a diversified etf since it's a large sum and volatility is uncertain in this economy.

Will require more information regarding what you're investing. If it's a global etf like IWDA then one time $20k shall still be safe. If it's into specific stocks, be careful.