It depends on who you ask, some people believe the good bacteria that has been killed off/reduced can return but it is a long process(probably 2+ years). Others say that some strains will never come back. Unfortunately we still don’t know every single strain of bacteria in our gut. But there is at least 6-700+ strains of bacteria in there. Just avoid antibiotics at all cost unless it is life threatening is my advice, but I’m not a DR.
Fecal transplant is a way to restore the good bacteria more permanently. But a lot of people are too grossed out to try it. I’m just waiting for some test results to come back before I try it.