Hello

I have a question: I have to mill several slotted holes into a part.
With 2,5 and 3,5 diameter and a length of 60-75mm
The drill holes are not in the centre.

What must I do? First drill slowly with little feed and then faster when the drill is further in the material.
I fear that the drill could break off in the first few mm with a chip length of almost 90mm.

Material is ETG 88.

Many thanks in advance