How widespread can this equipment be though that none has ever been recovered as a weapon of the enemy?
If you have enough resources to start targeting low to mid level staff, then you have to have a lot of practical devices which are mobile.
While it's plausible the US has in fact recovered a whole bunch of them and kept it secret...why? The microwave attack rumor is common which means everyone is looking into whether it can be done. Announcing you found the device and not showing pictures even - but instead nothing. No detectors either and as noted above detecting RF would be extremely cheap - deploy a couple of devices and you've got a direction finder telling you exactly where it's coming from.
Havana syndrome could be a lot of things: the US is a big place, and decades ago food safety standards and additives were very different - MRE composition or catered food service would have had regional characteristics, but so would just random events happening randomly - on a long enough timescale you'd get a cluster of health issues from the people you sent through one part of the world but not another. Once you're into talking about multi-decadal outcomes this gets even fuzzier.
It could be extremely widespread if it is used by intelligence agencies, especially if the attacks are conducted by official embassy staff with diplomatic immunity abroad or by domestic intelligence operatives in the country.
For example, I don't think CIA operatives could easily snatch a car full of FSB agents on the streets of Moscow, confiscate their equipment, and get away with it. The same for Havana. (If they had a way to detect the attacks, they might try, but the point is even then it wouldn't be easy. AFAIK, operatives generally do not attack each other directly on foreign soil.)
If you have enough resources to start targeting low to mid level staff, then you have to have a lot of practical devices which are mobile.
While it's plausible the US has in fact recovered a whole bunch of them and kept it secret...why? The microwave attack rumor is common which means everyone is looking into whether it can be done. Announcing you found the device and not showing pictures even - but instead nothing. No detectors either and as noted above detecting RF would be extremely cheap - deploy a couple of devices and you've got a direction finder telling you exactly where it's coming from.
Havana syndrome could be a lot of things: the US is a big place, and decades ago food safety standards and additives were very different - MRE composition or catered food service would have had regional characteristics, but so would just random events happening randomly - on a long enough timescale you'd get a cluster of health issues from the people you sent through one part of the world but not another. Once you're into talking about multi-decadal outcomes this gets even fuzzier.