Yes I think this pattern will get much clearer in the near future. We already see these links with chronic illness, depression, etc and gut dysbiosis. One thing I wouldn’t count out is the effect of lingering virus or viral antigens causing regular immune system stimulation leading to various unexplained illnesses to varying degrees. They also can contribute heavily to gut dysbiosis which may be linked with serotonin production and other things. Knowing how bacteria plays together is one thing but we also need to understand how pathogens can affect our guts as well!