You can't for example see ME/CFS or Long Covid neural damage on a typical MRI but when you do autopsies you find a host of problems including complete viral RNA and intrusion of the immune system that shouldn't be there. Given the similar presentation of Havana syndrome to ME/CFS it would seem sensible to look for some of the similar markers of vascular brain damage with the process developed there by Jared Younger and we will likely find a similar type of brain abnormalities. Just because it doesn't appear on MRI doesn't mean its the only type of test that can be done to find abnormalities in the brain, there are a lot of possibilities for further tests in similar presentations of symptoms.