Maybe read the instructions on the form 1040-ES you linked to?
"If, after March 31, 2020, you have a large
change in income, deductions, additional taxes, or credits
that requires you to start making estimated tax payments,
you should figure the amount of your estimated tax
payments by using the annualized income installment
method, explained in chapter 2 of Pub. 505. If you use the
annualized income installment method, file Form 2210,
including Schedule AI, with your 2020 tax return even if no
penalty is owed."
Also, if you go up a couple of posts I shared a way to get around that, basically you can make yourself a W-2 employee and do a big withholding in Dec. A little bit of a pain if you don't already run a business, but not something you couldn't accomplish with a day's work.
in chp 2 of pub 505? it defines expected AGI as total income minus expected adjustments.
but it then defines total income as "Total income includes all income and loss for 2019 that, if you had received it in 2018, would have been included on your 2018 tax return in the total on line 6 of Form 1040."
how are traders supposed to know in march, what their total income will be for that year? they keep alluding to using the previous year as a reference, in which case this just goes back to the 110% method mentioned earlier.
your workaround is neat i will admit.