Recovery rebate credit omitted by tax preparer who filed taxes online - can I amend online with turbotax?

Background:

A paid tax preparer completed a 1040-SR and filed it electronically.  The preparer was informed that the second economic stimulus payment was due but never received (direct deposit account changed - old account was closed in November 2020).  However, the preparer failed to claim the Recovery rebate credit that was owed.  A completed "Recovery Rebate Credit Worksheet" clearly reveals that the full $600 was payable.

Questions:

I have searched the IRS and TurboTax websites and have not yet found an answer to these two questions:

1. How can I verify that my 2020 1040-SR was submitted electronically by my tax preparer and that it was accepted by the IRS (so that I can electronically submit a 2020 1040-X amended return)?

2. I now do not trust my tax preparer.  Since the original 2020 1040-SR was submitted electronically by a paid tax preparer, how can I prepare and electronically submit a 2020 1040-X using turbotax (or irs web site)?

Notes:

(a) I now own 2020 home & business.

(b) I hope that it is possible to complete the 2020 1040-X without the full turbotax interview (perhaps using "form view" for 2020 1040X and overriding the fields to enter the 2020 1040-SR data and amended values).

(c) I would like to file the 2020 1040-X electronically using turbotax or irs online, even though my original 2020 1040-SR was filed electronically by a tax preparer (probably not using turbotax).

With *many* thanks!