Islands:
I define areas like that which have no connection to the rest of the model on the layer.
Like those tree branches bending down and with their tip BELOW the rest of the branch.
These have to be printed with support from below and if VERY small and thin ARE a PAIN for FDM.
Upscaling by 500% results in your 0.174mm branches still being just under ONE mm thick.
That is literally like trying to print a dot.
Anything OVER 0.4mm wide is not a problem IF it is horizontal, your tree parts are from it.
The video you linked shows architectural design features offered by a printing company but neither specifies how the trees were created nor if they were printed in one piece, not even if the fluff was added manually.
I know for a fact that there is companies selling trees, shrubs and lots more at a scale used for most design and hobby projects.
One example is the world of train models.
I tried printing something similar to a tree with my resin printer and gave up trying.
Certain things just can’t be printed and need to be created the traditional way 