Yerba mate is differently caffeinated (hopefully you know decaf is really just half caff), plus it's kinda fun getting the gourd and the bomba. I recommend meta mate out of Berlin, they export the good stuff out of Brazil, much greener than grocery store / commodity varieties

There's mushroom coffees that claim to be stimulating, you can look at four sigma for that, tho my favorite was their instant coffee with cordyceps, good pre workout.

Then there is breathwork of the wimhof variety, "get high on your own supply" deep breathing and ice baths, all natural.

> hopefully you know decaf is really just half caff

In the US, to be labelled as decaf more than 99% of caffeine must be removed. The EU wording, iirc, is a bit weird but amounts to essentially the same requirement.

So decaf really is decaf. The only people who might notice some effect are those who never drink any caffeinated drinks at all, and even then I'd say they wouldn't notice much.

Regarding decaf. "The authors suggest the following standard values for the United States: coffee (5 oz) 85 mg for ground roasted coffee, 60 mg for instant and 3 mg for decaffeinated" https://pubmed.ncbi.nlm.nih.gov/8603790/

just get unsmoked yerba and never drink it burning hot to lower the risk of esophageal cancer