Little background - I'm about as secular a person as you'll meet, I also came into pu'er rolling my eyes into the back of my head whenever I heard a comparison between qi and cannabis or opioid-like effects. I figured it was coming from people with limited-to-no experience of either. I don't meditate, though I do have some small experience "leaning into" psychoactive effects and making the most of chemically-altered states.
I held onto that for about nine months before I was forced to admit the potential for legit psychoactive/physiological effects from teas. Whether or not you attribute it to mystical forces, it's hard to ignore it when you start sweating bullets, or feeling a comfortable (and yes, broadly opioid-like) floaty feeling in your head, or feeling your skin "buzzing" all over, or a growing feeling of mental clarity. It's very inconsistent, very personal, and often something you have to "lean into" the way you might have to lean into a low dose of a psychedelic, but it's certainly real in the sense that some people experience effects that they probably couldn't talk themselves into.
To quote (I wanna say) Hobbes, pu'er is drugs.