Bread from the machine always too soft, can't be buttered
I would leave out the bread improver, the olive oil, and the milk (use water) and see what happens. Both the bread improver and the fat make softer bread. 

If this is not sufficient and/or you really insist on resilient bread, the next steps are 


look at the gluten content of your flour and use a higher gluten content if yours is low. American bread uses bread flour with 12-13% for example. If you can't buy such high gluten flour, you can buy gluten powder and mix it in. 
start with ice cold water
add a gram of vitamin C (crystals, not a pill) at the beginning. 


All three make stronger gluten, to the point that if you do it all at once, the dough might even be too hard to knead. 

Another thing to try is to make darker bread, as whole wheat flours add more body and also have a bit more gluten.