This is something that will require extensive explanation to the IRS (and to the Roth IRA custodian). Given that you were doing backdoor Roth, presumably you have no other amounts in traditional IRAs. The second contribution that was an excess traditional IRA contribution became an excess Roth IRA contribution when converted to Roth. Because you withdrew everything from the traditional IRA, that effectively constituted a return of contribution from the traditional IRA and the movement of this money to a Roth IRA constituted a regular excess contribution to the Roth IRA. You'll have to explain this to the Roth IRA custodian so that they will do a proper return of contribution from the Roth IRA.
You'll likely have to submit a substitute Form 1099-R (Form 4852) with code 8 in place of the one with code 2 to report this distribution as a return of contribution from the traditional IRA. You'll also want to make sure that the custodian prepares the 2021 Form 5498 from the Roth IRA reporting a regular contribution, not a conversion contribution, so that this will match up with the code JP 2022 Form 1099-R that will report the return of the Roth IRA contribution (also reportable on your 2021 tax return).
