Credit card cash back, it’s easy to get 5% on most purchases. That’s $1,000 tax-free a year for $20,000 expenses you’ll have either way.
In the US $20k of credit card expenses is not insane as an adult living by yourself.
After factoring in groceries, gas, insurance, utilities, a few dinners out and a couple flights a year, that’s very reasonable.
I am a relatively frugal person who spends $40k a year in a HCOL area in the US (but get paid 25X that fortunately), and $20k is my credit card spending, I basically put everything on my cards except for rent. Cards are in autopay every month, so no risk of extra fees. I also have enough financial discipline to obviously not spend more than I strictly need to, I am a very aggressive saver actually.