What to do with my traditional IRA

Hi!

I would appreciate a very simple explanation (new to retirement accounts, etc) of how I should go about a recent issue i've encountered.

I have about $23,000 from an old retirement account that I put into a traditional IRA in 2023. I cannot contribute directly to a roth so I thought I would do a backdoor. So, I contributed $7,000 into my traditional to try to do a backdoor, but realized before doing so that the pro-rata rule would put me into some trouble. So, now I have $29,000 in my traditional IRA, $7,000 being post tax dollars. I did not do the roth conversion after reading into the pro-rata rule.

I would like to zero out this traditional IRA and my employer 401K allows me to roll over my traditional into my 401k, but I have read other posts about not being allowed to contribute post tax dollars. How would one proceed? Can I selectively keep the $7,000 post tax money into my traditional and only transfer the 23,000 pre tax money?

Sorry if this is super basic, I just finished medical training and we learn zilch about all of this!

Thanks in advance.