I have $40k sitting in savings — should I put some in CDs?
Yes. You won't need ~$28k of it for at least 12 months. I'd build a 4-rung ladder: $7k each at 6, 12, 18, and 24 months — blended yield 4.65%, vs. 4.20% in savings. That's about $126 more per year, with $7k freeing up every 6 months.
Build it.
Opened all four CDs and set auto-roll. When the 6-month rung matures, I'll re-evaluate the curve — if longer terms still pay more, I'll roll it to the back of the ladder. If short rates are higher, I'll keep it short.