Obviously I think the fees are pointless.
It's silly not to pay for everything on credit cards here, when you can get 3-5% back on anything with the right card. That's around $4k/year if you spend $100k before even accounting for doubling on some cards and other benefits like travel vouchers, Uber credits, and free insurance coverage. (Minus a $600-$1000 a year in annual card fees for high end cards.)
There used to be a 3% cashback on everything card with no limit. Now 2% is the best and difficult for most people to get.
You can get 5% credit back with an Amazon Prime card but only on Amazon.
Most other 3% or more back are either limited to a niche category and/or capped. (Like 6% back on groceries, but only for the first $6k).
So unless you're spending like 200k net a year on life expenses, it's pretty easy to get the max returns.
On the other hand, with debit cards money is withdrawn from your account when a fraudulent purchase is made, and you need to wait for your bank to complete an investigation to reimburse you. They also tend to have rather stricter reporting standards in that if you don't report fraud promptly, you might be stuck with (some) liability.
Either way you'll typically get your money back, but the hassle is much reduced with credit cards.
If a merchant posts a fraudulent transaction against a credit card, you'll most likely get your money back. If a merchant posts a fraudulent transaction against a debit card, you might not get your money back.
More dangerously, if your debit card credentials are skimmed and used to withdraw money from your account by any means other than the retail debit-card payment system, you won't get your money back.
How in the world would a tpical person spend that much? That's over $8000/month with credit cards!
Also... aren't your 5% cards capped at like $1500 spend per quarter ($500/month)?
Do you use cash back cards in your own life, and does your usage even vaguely match the numbers you suggested here?