Is there a distance so small it can't be further divided?
There are certainly distances that WE (humans) can't further divide. The thing is we conceptually measure things by looking at them and comparing them to something else.
The problem is that if we go to the ridiculously small, we a) can no longer consider "looking at them" as a neutral act, but it becomes an active interaction changing the thing that we look at and b) we run out of things to compare something to.
So idk for a simplified picture think of "looking at something" akin to how bats "look" at something, that is they send out a shockwave of air pressure towards a target and measure what comes back. Now the shockwave of a bat scream is hardly going to move walls or humans, but if you go towards ever smaller objects it becomes more and more likely that the force of that shockwave is able to blow away the object itself. So by "looking at a thing", you change the thing itself and so the result of the measurement no longer tells you what the object looks like, because by the time you get the results the object might be different due to your interaction with it.
So you need not just the location, but also the momentum (where it is going and how fast), though these are 2 different measurements and they impact each other. That is measuring the movement of something means that it changes location and measuring the location sets a thing in motion. So there are limits to how accurate you can measure either of these two.
So you end up with something like Planck length and time, which mark the theoretical boundaries of our ability to measure things. That doesn't mean that there aren't things smaller than that, it just means that we can't see them and don't know of any measurable physical effects on those scales that we could compare them to.
So that's a very simplified version of the physics. Conceptually, though there's nothing stopping you from ever further divide something. Like 1/2, 1/4, 1/8, 1/16 ... is essentially just 1/(2^n) where n is part of the natural numbers. And as the natural numbers are infinite, you'll never run out of a next number to further divide that.
So yeah if you where to always take steps cutting the remaining length in half and would take the same time for any such step, then you'd essentially NEVER reach your target. In reality though once you've hit the Planck length you wouldn't be able to tell the difference between stagnation and progress making this kind of a useless endeavor.
Also if you were to shoot a real life arrow, then you'd not take equal amounts of time for a step of cutting the distance in half but you could assume an almost equal speed during these space/time intervals.
Meaning that if you have a constant velocity and a decreasing length, the time it takes to travel that distance is also decreasing by a factor of 2. So the distance to target is approaching 0, but so is the time to arrival.
And even if you argue, "but the arrow looses velocity over time". Sure but the rate of loss of velocity also approaches 0 with the difference in space and time approaching 0 and likely much faster than the other 2 so that difference becomes pretty negligible.
And in the limit of n going to infinity the sum over 1/(2^n) is 1 so you've traveled the whole distance in the whole time.