If you get a CD you don’t have that option right?

If you get a CD directly through a bank, it will have some early termination clause. Usually forfeiting some amount of interest, which is lower risk than trading on the market.

If you get a brokered CD, then you can sell it on the market like any bond.

is the slightly higher yield worth the additional “risk” (if any) of buying treasury bills over a CD?

In an academic sense, a CD would require both the bank and the government defaulting, whereas a treasury bill would require only the government to default. So technically lower risk.

But that is purely academic, as if both of those were reasonable risks then you would not invest in any US dollar denominated assets at all, or anything linked to the USA regardless of which currency it pays in.

You are creating a fake problem.