alt Hacker NewsI gave up on optimizing and just use the Robinhood Gold 3% cashback card everywhere (except Amazon/WF, where I use their 5% Chase card). I can probably get more than 3% cashback in some categories on other cards, or more ROI by switch to points, high-tier cards like Chase Sapphire, and churning, but I just don't care.
The gain of a few thousand per annum is not worth the mental distraction.
I do the same. Just a single card for most spending, but has a bunch of handy features. I pay $50 a year for that, the convenience in case it gets stolen etc. I will say though that it's a little annoying to constantly transfer to the brokerage and then to the bank, but not too bad.