> maxing tax advantages

any retirement/investment account that gives a tax advantage has a yearly contribution limit

so when they ask if you have maxed your tax advantaged space they mean have you put $20,500 in your 401k (TSP), $6,000 in a Roth IRA, $3850 in a HSA, $8000 in a 529, etc.

paying low to no taxes now isn't relevant, its the account that provides tax advantages now or in the future or both, regardless of your current tax situation