Also, I kinda dread factory resetting my phone. As I had swapped from the S10 (I had in November of last year, not learning it would stop receiving support), and deleted most stuff from the S10 after the SmartSwitch stuff.
So, I'm unsure if I could get most of my stuff and data back after the factory reset.
I very recently was having the exact same issue and this is what I did to solve it...In settings, then into the software update, there's an option to download updates automatically via wi-fi. I turned that off, then went through the update again, and the update finally worked. I don't know if what I did is the fix for this issue or if it was simply a fluke, but it fixed the issue for me. I hope this helps.