Do you know what screen to use if taxpayer, due to covid, wants to reduce underpayment penalty on self-employment tax?

As of now, there is no input for what you are looking for.

If current year liability is used to determine your client's 2210 penalty and assuming your client chooses to defer 50% of the SE-tax, all the numbers should flow correctly without your intervention (unless, of course, annualization is to be used).

On the other hand, if your client does not choose to defer the SE-tax, you will likely need to manually override the computations.  If you look at the draft form and instructions for F.2210, you will notice that the only instructions for deferral adjustment are under the section for annualization; their logic probably is that all the numbers will just flow naturally from Sch SE to Sch 3 and F.1040 and then to F.2210 for all other taxpayers who defer their SE-tax.

There's no telling whether F.2210 and its instructions will be updated to provide additional instructions in relation to folks who opt not to defer SE-tax.  Unless the IRS provides specific guidance (similar to the worksheets included in Pub 505 for 2020 ES-tax projection with SE-tax deferral), I doubt Intuit will build its own tax logic to address that.

Just in case you're looking at reducing the minimum annual payment based on prior year exception, I don't believe you can make any such adjustment since §2302(b)(2) of the CARES Act should not be applicable to §6654(d)(1)(B)(ii) in letter or spirit.

You have asked this twice. The first one is being answered, here:

https://proconnect.intuit.com/community/lacerte-tax-discussions/discussion/what-lacerte-screen-is-used-to-elect-deferment-of-self/00/112981

No need to keep starting a new topic on the same issues if you already have a topic on the same issue. Just keep working in that same topic.