Eyeballing your design, it looks like your pentagon is not regular, but 2 sides are longer. I haven't measured, so it could just be an optical illusion

That is very small. I'd say on the edge of doable (with accuracy) for the davinci. If I'm printing anything that small, I'm assuming the dimensions may not be exact and try to design to make it... flexible in application. If that makes any sense.

Try this though. Thinnest walls you can go (Heck, thickest might work well too, try both), .2 layer, 100% infill (or whatever the max is), slow speed. It's small enough that the grid produced by a low infill % might end up skipping a few layers, and weaken the structure. It's so small that even if you got 25% infill on every layer, it's probably more than 50% given the volume you're trying to fill. I really haven't noticed a difference with print speed, but as small as this is, it can't hurt. Try it at normal too to see if that actually makes a difference.

Try those settings. If you are still having issues, I've found that for thin, tall objects, the davinci does not let the previous layer bond enough before starting a new one, sometimes leading to 'smearing', which can compound into an ugly mess. Create a hollow cylinder just big enough that the object can fit inside, maybe even a bit bigger if it needs more time. Make the wall thickness just big enough that the slicer (XYZware) renders it as solid, I think .2mm thickness works for me (?), a little trial and error will be needed. Good thing is, you won't print until you get a good slice. The cylinder will add material to each layer, giving the main print more time to cool and settle. Yes, the cylinder is wasted material, but it can be recycled. I've had good success printing tall thin objects using this technique.