Earlier quoted context omitted.
You can't really max out a Roth IRA (that's an illusion). Backdoor contributions are unlimited.
Weird, i thought its 5500/year. That's what you can do with betterment at least....
With a backdoor Roth, you contribute to a normal, post tax IRA, then convert to Roth. However, if you have a rollover IRA, then you can't do it without taking a tax hit.
However, I have heard of people putting more than $5500 per year in a Roth. Search for it on the Bogleheads forum. I can't remember the details, but your employer needs to be on board as you contribute to a 401k, then do some conversion.