I think when most people opine on tea there's an unspoken, and often unrealized, assumption that it's uncaffeinated tea. Because often when people discuss the relaxing aspects of tea or making tea what's really being described just seems like a purposefully self-occupying nothing action that offers little in the way of chemical stimulation. Which is fine, I'd agree such things can be both relaxing and good for giving ourselves time for certain kinds of reflection, but try it with a competitively caffeinated tea and I suspect the reality would be much less relaxing than the hypothetical.
Does such a thing exist? Usually "tea" is made from tea leaves and other similar drinks are called "infusions" or "herbal tea" instead. I have never heard of decaff tea, but maybe it is common in other places?
Most tea brands in the UK have a decaf version e.g. https://www.pgtips.co.uk/our-teas/tastydecaf . It tastes almost the same as black tea although I think I can detect a slight difference. My understanding is that there's a post-process treatment of the leaves to remove the caffeine.
You're right that drinks not brewed from camelia sinensis leaves should technically be called an infusion or tisane. That includes fruit "tea" and infusions like rooibos, chamomile, nettle, or maté. However it's very common even in the UK to say "fruit tea" or "chamomile tea".
I disagree. The kind of wakefulness you get from a strong caffeinated tea is very different to the kind you get from coffeee. It's like a relaxed glow whereas coffee is an animated buzz.
