Third stimulus https://ttlc.intuit.com/community/tax-topics/help/how-will-the-stimulus-package-impact-me/00/1393859
Note, In particular, getting the new (expanded) child tax credit has nothing to do with filing your 2020 tax return. Whether you already filed, file now or file later, the additional money will not be part of your 2020 tax refund.
For the unemployment $10,200 exclusion, you should wait for the IRS to issue instructions. See https://finance.yahoo.com/finance/news/claim-10-200-unemployment-tax-213344752.html
