I need some quick advice. How do I trade on Robinhood to get the best prices?

Got the 3% back on everything Robinhood Gold card (likely because they saw I am a revolver that doesn’t miss payments OR I had 100% of the deposited assets I made under their control for over half a decade.)
ANYWAY. I’ve noticed to buy BTC with Robinhood they’re charging me a 0.85% fee. So I tried a limit order, but it’s not going through. Do I just need to wait a while for it to go through? I’m getting confused. I’m not saying Robinhood is “scamming” but I am saying I don’t want to give up almost all of the benefit of my 3% back card just to get an instant buy order to go through.

Any advice? AI is starting to annoy me.