Switching from TT online to desktop after finished online

I have used TT online for years, but am thinking of purchasing a desktop version for PC to save money.  I have several questions I couldn't find answered (easily) in the community:

 

1. I have nearly completed my 2020 taxes in TT online.  I see that I can perhaps save this as a file to import into the desktop version, but I can't find any discussion as to how cleanly this works.  Will I still have to do a lot of re-entering of data the first time I use TT desktop? Will it carry over W2 and downloaded 1099 info for example?  I've spent many hours entering info online and don't want to have to redo it all!  Also, does the desktop remember all of your basic info, SSN etc from year to year?

 

2. It isn't clear to me if you have to buy a new desktop program/license every year? Or do you buy it just once, say through Costco, then it updates each year for free?

 

3. I do download 1099-div and 1099-int forms, which online seem to require Premier, but some posts mention the desktop deluxe version might be able to do this too (div, int, stock sales)?

 

4.  It seems that e-filing the state return costs an additional $20 - is this done through the TT desktop software (it takes your money and handles the transmission), or do I have to to upload some sort of file to the state (CA)?

 

Thanks for any answers!