NO NO NO ... you cannot enter the payment of the 2020 balance due anywhere on the 2020 return. The return will always reflect the balance due even if you have already paid it. That is just the way it is. You and the state will know it is paid so the return doesn't need to reflect the payment and it never should.
For instance, if you went to a paid tax pro and walked out with a paper copy of the return showing you had a balance due then later paid the balance due the paper copy of the return would never show the payment and neither will the electronic copy of the return. Done, end of story.
