Welcome to the forum.
Using the set focus tool is a much better option than manually inputting focus height. To do this, click the three dots in the interface, select set focus, move your cursor to the area of the material where your design will be and click. Watch that the red laser beam lands squarely on the material. If it doesn’t, repeat the process.
The Glowforge does not have a dpi setting. It uses lpi (lines per inch) for engraving. Bamboo is a very inconsistant material. It is not actually wood - it is grass. The search function will reward you with many suggested settings. Here is one post that you may find helpful. Bamboo cutting board with settings used
The community may be able to be more helpful if you supplied a photo of your results.