What % of Savings Account to Transfer to HYSA?

I have about 20k in my regular savings account. I’m trying to determine what percentage of this I should transfer into a HYSA, add into my investment account, or do something else with. What factors would you consider in making this decision if it were you? I’ll return to the U.S. in a couple years where I plan to buy a home and a car. I’m sure these factors should play a role in this decision.