Deodorant or anti-perspirant or none of the above.

[zion zig zag]

I know they market Merino for all sorts of conditions ....
But, apart from wearing the Merino bikini undies (they do stay fresh in sweaty sports in the tropics), I would/have never wear/worn any other Merino on other parts of said body in the tropics.
Either I'd want to be wet and cool (beach or some wet activity) or would want a thin synthetic top.
I mean, I would bet money NO ONE would wear any sort of Merino top, thin or perforated or otherwise, in the tropics
... purely for comfort and moisture retention issues.
I am of the opinion that Merino feels better when the temperature on the other side of the fabric is quite a bit cooler. The colder, the better.
Cotton is your tropic friend.
The exception that proves the rule.
Cotton and synthetics.
100% of sheikhs and surfers agree.

Meh, I've worn merino t shirts in SE Asia and Central America and I think it works great there. Dries relatively quickly after getting caught in the rain and no stink.

[old goat]

Hilarious bump. We're not supposed to be close enough to smell each other. Farts and BO are powerful weapons against the Covid.