Form 2210 has gotten better with the release of version R22. Line 26 column (a) now properly propagates to line 20 column (c).
Regarding the second bug I reported above, TurboTax is still failing to include on Form 2210 line 19 column (a) any estimated tax payment from line 2 of the Tax Payments worksheet even though the date entered for that payment is 07/15/2020 or earlier. The workaround to this second bug still works.
