This week Clark suggested that you could only max on your Roth IRA and Roth 401k in the same year, contingent on not exceeding the income limits. I confirmed with a vanguard ira specialist that if your income limits exceed the Roth IRA limits, you can max out doing a Backdoor Roth IRA, and simultaneously be free to max out on your Roth 401k.
Link to a very helpful post on backdoor Roth IRA’s