Re wax myrtle...
If these shrubs are at your house... I would attempt transplanting the babies that are sent out in attempted colonization.
As above, not sure this plant is a good candidate for taking cuttings...
I usually allowed them to get large and would cut to the ground every 4 or 5 years to control.... and this made the suckers available for transplant.
That was when I was in the clay...
Here in the sand?
I keep planting them, but they don't thrive, eventually perishing after 4 or 5 years of barely clinging to life.