I mean, when I googled supply-side economics it said it was another name for trickle-down economics. I'm interested in how you'd say they differ, honestly, not trying to be argumentative.

I found at least found one analysis (by a left leaning think tank, so take it for what you will) https://www.americanprogress.org/article/the-failure-of-supp... that seems to show that supply-side economics hasn't panned out.

It seems obvious that there is an optimal tax rate, too much or too little is bad. But I'd definitely say right now we are far far on the too little side of things.

You’re describing the Laffer curve.

Much of Reagan’s trickle down stuff was based on the idea that we were on the wrong side of the peak.

I don't know where you're looking, but if you go to the first result for trick-down economics, the Wikipedia page, within the first few lines it mentions how the term is used, and how it was created by detractors of supply-side economics. It's never been a real policy.

    "the term 'trickle-down economics' was popularized by Democrats in the US to derogate Reaganomics"

    "not to be confused with trickle-down economics"

As for whether supply-side economics actually works, to say it "hasn't panned out" I think, is really oversimplifying. Has capitalism (efficient markets but also environmental decay) worked? Has socialism (universal healthcare but also the military) worked? It depends on who your asking and in what regard. In some ways yes and in other ways no. The category is too broad.

Also, just as important as how much we tax is where we tax. Carbon tax (very good) vs stamp duty tax (very bad). Competent policy often allows you to have your cake (supporting government services) and eat it too (not sacrificing growth).