Hi Gunter.

Here is an example of a text with a 5mm recess.
The letters "Tw" have walls with a 20 degree inclination, milling on the contour with an angular cutter and selecting an island.
The letter "in" has to be modeled and engraved according to the model with the selection of the appropriate milling cutter as each wall has its own slope.

https://disk.yandex.ru/d/TEqG8MisVXH9rA