There's the Sniper Bow, which is made from three artifacts that give a total of +30% to archery. Although in my version of the game, clicking on the Sniper Bow doesn't show this information, but, for example, the Heroes wiki says that it also gives +30% to archery, which makes sense.
That's fine.
Question: if I have both the Sniper Bow and, say, the Cherry Wood Bow (+5% to archery) in my active slots, will they stack? Is it worth investing in archery in this way? Will it work?
Added after 23 hours and 10 minutes
I tested it today, and it seems like they don't stack.