Did not file form 568 for Year 2019. Did not pay Annual tax for year 2019 and year 2020. What to do now? And how to do it?

If @DawnC could help:

I have been using TT premier for the past 4-5 years.
I created a single member LLC in CA on Sept 10th 2019. It did not make any money in 2019 and I mostly had expenses so I did not report any of it in my 2019 Federal or State taxes when I filed online using Turbotax premier. I did not even know what a form 568 was. I did not know I had to pay a 800$ annual tax>
Everything went smoothly. Got my refund and I have not gotten any notice from FTB. 

Fast forward to now February 2021. I find out that I have to pay an annual tax (which I did not pay for both years 2019 and 2020) and I find out I have to file form 568 for my single member LLC for the year 2019 and for the year 2020.  I cannot create an FTB account online as it requires at least one prior filing. So I chatted online via the chat service for people who dont have an FTB account. The person recommended me to pay online via the WebPay service and make 2 separate payments: one payment of at least $840 for the Sept 2019- Dec 31st 2019 period. And another payment of 800$ for the Year of 2020. Since we did not know how much penalties I had incurred I went ahead and made a payment of $900 today 02/24/21 for the first period 09/10/19-12/31/2019.  I have not made the second payment for the year 2020 yet due to not having enough cash.

My questions are:
A) Do I need to amend my 2019 Federal and State tax returns? Or do I just go ahead and file Form 568 for the year 2019 (which I found on the ftb.ca.gov website).
A1) If I have to amend my 2019 Federal and State tax returns, do you know if I can do it online? Can I use TT 2019 Home and Business? What do you think is the best way to proceed?

A2)  If I can just go ahead and file the 2019 form 568, what is the best way to proceed? Can I do it online via ftb.ca.gov? Or should I print and mail it? Would you recommend me to use TT Home and Business just to file that form 568?

B) Since I did not get any notice from FTB, How do I determine how much money I owe FTB? And how would you work it out into deductions for that year (would you try to count the $900 as deduction at all)?

C) for the year 2020: Can I use TT Home and Business for my single member LLC and will it allow me to file online? Or will I have to print and mail the form 568 separately?

Thank you so much for any help and any additional comment/suggestion you may have on my situation!