I contributed to my 2019 and 2020 traditional IRAs in January 2020 and converted them to Roth IRAs days later. Why did my federal tax due skyrocket?

[WhatTheTax]

I followed this guide: https://thefinancebuff.com/how-to-report-backdoor-roth-in-turbotax.html but it mostly covers the case where you contributed and converted in the same year before 12/31 of that year.

For my 1009r from vanguard, it says I have a gross distribution of 12,000. Must have been from the two 6,000 conversions for 2019 and 2020.

I've never contributed deductible cash into my Traditional IRA. I've only done Traditional to Roth IRA rollovers. Should my total basis be zero in that case? Since I always convert my Traditonal IRAs to Roth IRAs asap, should I be putting 0 for the value of my traditional IRAs?

I must have input something incorrectly, because after filling out my IRA section of the Deductions and Credits tab, my tax owed did not budge at all. It stayed the crazy amount it shot up to when I filled out the IRA section of the Wages and Income tab. If I filled out everything correctly, the taxes owned should have been the exact same as it was before I filled out the IRA section of the Wages and Income tab, right?

[WhatTheTax]

I put $6000 for my total IRA basis for 2019 in both the income IRA section and the deductions IRA section and that seems to have given me a refund with the two Roth IRA conversions tax free.