You don't "rollover" the ROTH contribution but instead you instruct the IRA custodian to recharacterize the contribution + earnings to an IRA. If you make too much to take a deduction for the IRA contribution then it can be considered nondeductible and a basis is tracked.
I suggest you wait to make any IRA contribution until after the year ends so you know how much you can put into which account. The TT program will let you know the limitations so you know exactly how much you can put in which account. You have until the filing deadline to make the contribution for the prior year.
https://www.fool.com/retirement/plans/401k/contribute-to-401k-and-ira/
