The simple answer is, you know the watch is a construction because you can compare it to natural non constructed items such as a tree.
So you know the watch infers a watchmaker because you know what a non designed object looks like, so that being the case why would you think the world is designed because it obviously isn't because we know what a designed object is.

The usual answer to this is that yes individual bits of nature don't look designed but they work together perfectly and DOES look designed.
Except of course they don't, but even putting that aside, the individual bit of a watch ALL look designed so if a designed systems is made up of designed components in a watch, why do the individual bits of nature NOT look designed as was just admitted?

Lived reality for most of us is at best more like an absent watchmaker situation.

I assume you're referring to some form of "argument from complexity" with the analogy being if you find a watch lying around you don't assume that the parts just flew together of their own accord, right? And that is somehow made falsely equivalent to natural selection?

This ignores chaos theory and the fact that under the right circumstances life is self-organizing in ways that overcomes entropy. I would bone up on resources around that and refer them to those resources to further educate themselves. 99.9% of the time they won't take you up on it, but it's not your job to tutor the unwilling.