Z Position moving up and down

Hello, i am new here and have a Little Problem with my construction.
Sorry for my bad english.

first i have a simple Question, how is to use the Focus Z Bottom? it is the Right at the Laser Movement.

now to my Problem, i have a Tronxy X5S based 3D Printer with 5W Laser for engraving and cutting.
How can i say Lightburn, that he have first to move my Z Axis to a specific High that i have optimal Laser Focus. If i Move it Manualy and take off the Z Axis it works. But Some Times i have peaces that have different highs that i want engraving. So i Need an Offset of the High of the Object aditional to the Focus High. Now i tryed to work with the Z Offset in the Layer Setting.
If i choose only the Fill Option ti works good. But if i coose any Line Option at engraving the
sometimes the Z Positon driving to 0 and than back to the Offset High.

Why he do like this? How can i fix this Problem?

Thanks for help and i hope you understand this Problem

For better Understanding i put a sample of the gcode here.
And i marker the orders in blod. They dont be needed, why Lightburn make this?
Need only at start of the Gcode one G0 Z41.

G1 X0.32 Y-0.34
G1 X0.3 Y-0.37
G1 X1.83 Y1.14
M106 S0
G0 Z-41
M106 S0
G0 X-14.32 Y-2.19 F0
G0 Z41
G0
M106 S51
G1 X-1.96 Y-0.97 F6000
G1 X5.79 Y-11.6
G1 X1.97 Y0.98
G1 X-5.8 Y11.59
M106 S0
G0 Z-41
M106 S0
G0 X-1.07 Y2.16 F0
G0 Z41
G0
M106 S51
G1 X-1.13 Y2.26 F6000
G1 X-1.96 Y-0.98
G1 X1.12 Y-2.26
G1 X1.97 Y0.98
M106 S0
G0 Z-41
M106 S0
G0 X-7.26 Y-0.61 F0
G0 Z41
G0

The reason is that LightBurn is cautious. Since you appear to be using a Z offset, not a material height, I cannot assume that the offset is “safe” to leave on at all times. If you were engraving the bottom of a bowl, for example, I would move to the start, lower the Z, do the engraving, lift the Z, then move away. If I moved the Z down and then moved the controller, you would hit the side of the bowl.

There is an option coming for GCode devices to optimize z moves, but it’s not done just yet:
image

Thanks for your fast Answer, i understand and will waiting for this new Option.

For all other i have to say this Programm works very well with my modifications at the 3D Printer.
So i can sign all my 3D Prints in one step.