Is a 529 worth it in this case?

You can withdraw the principle from the Roth accounts penalty free any time. It’s the earnings that have to stay in there for 5 years and you have to be age 59 1/2 in order to avoid penalties .

For those who can make such contributions, including students, it’s a good way to shelter assets from FAFSA.

No - that’ s the whole point of Roth vs. Traditional IRA.

Since you are putting in your AFTER tax (= NON-subsidized) money, you ARE permitted to withdraw whatever “own” money you had put in. So it’s a good way to “shelter” assets from the FAFSA form.

Only the tax-deferred (= subsidized) EARNINGS are subject to limitations.

You can put it in a hi yield savings account . We have Amex Personal Savings. It gives a yield better than current CDs and money is not tied up. There may be others. Just google High Yield savings accounts.