Honestly, I've had better luck just getting higher quality tea and cutting sugar from morning beverages entirely. (I don't drink coffee, but low quality teas tend to become bitter, which required sugar. Higher quality teas never become bitter)

These days, I'm cutting sugar across the board. Shredded wheat with frozen raspberries tastes better than honey bunches of oats anyways. And the sugar I'm eating is pretty much just for fun, like pie or ice cream. No reason to accidentally ingest 28g of sugar in a breakfast bar that doesn't even taste that good.

You can use Stevia. It's a natural product, zero calories. There is a more expensive option in monk fruit as well. I live on Stevia. It's easily available in groceries and stores, and reasonably priced too.