Even simple bread flour - yeast (or sourdough starter) - water
First you should try to get some strong bread-flour instead of all purpose kitchen-flour. Depending on your country, they will have different numbers, usually higher ones, but decoding flour between countries is complicated. You also can try a mixture with some rye or spelt or whole-wheat. I my experience, 50% wheat bread flour and the rest some random other flour gives usually good results no matter what you do.
If the bread is too bland, try adding a little more salt
. that might be the change you need. Overdoing the salt can kill the yeast. Another popular trick is to add baker's-malt (or honey lacking the malt) to give a little more taste.
Next is bread seasoning to add to the dough. In Austria a combinations of fennel-seeds, cumin-seeds, koriander-seeds and anis-seeds is popular. Example here in German
If those don't give any results you like, you can add more or less whatever stuff you like, from sunflower- or Pumkin-seeds over nuts, dried berries, olives, other whole grain stuff like linseed and barley up to grated carrots. That's what Germans are often doing. Personally I prefer a bread without to much chichi but a well-tasting crumb instead. You can't really go very wrong here, be creative.
With a bread-maker the crust will always be underwhelming, just like it is with bread baked in a baking-form.
After using the bread-maker for some time you might also realise, that make bread without the machine is nearly as easy and works just as well. The main advantage is that you can schedule the baking durng the night and wake up to fresh baked bread. On passages we made it in calmer times the duty of the second night watch to bake the bread so that the boat
smelled of fresh bread at sunrise in the middle of the Atlantic.
But this wasn't your question.