How do different virus and bacterial infections cause different symptoms?

Edit… Viruses do that and bacteria do something else. Still a valid question.

They each attack different things. For instance, rabies is a virus that attacks nerve cells, and travels on neural pathways to attack the brain.

Some bacteria attack the gut, while others thrive in a symbiotic relationship in one’s gut. Other bacteria travel to the lungs and cause pneumonia. Corona virus attacks the piratory system, but also causes what seem to be unrelated areas. (such as covid toes)/

It’s a combination of where the virus or bacteria attacks or lives and how our immune system reacts.