I agree, HMD's camera app does not work as I expect for macro shots.
In full auto mode it tries make as much as possible of the scene appear 'sharp', and the live-bokeh mode is often not suitable for what I want to do.
A workaround is to select Pro mode, set the manual focus as close as possible, take plenty of pictures while moving the phone towards or away from the subject gradually.
Another option is the Open Camera app by Mark Harman. It is a photographers camera app with macro mode (and much more) when Camera 2 API is enabled in its settings.
The minimum focus distance is 8-10 cm, with just a few millimetres depth really sharp at that distance, so I suggest take plenty of pictures and crop the best one for tiny objects.
It took me a few hundred pictures to get used to.