Hi welcome to the forum. Your photos are coming up as "Content not viewable in your region", which is not normally a problem from the Netherlands .Maybe try another method of adding them .
Just based on your description ( More wear on both outer edges than centre ) it does indeed sound like underinflation.
Have you checked the accuracy of the tyre pressure gauge you are using against others? Even a garage airline might be wrong. The Indirect tyre pressure monitoring system used on the Jazz would not necessarily detect low tyre pressure if they are all equally low.
If the pressures are definitely correct the problem is beyond my knowledge . Its best to consult an expert . Maybe a full 4 wheel alignment check is needed rather than the basic 2 wheel alignment done by most garages and tyre fitters. . This may require special advanced measuring equipment and expertise that not all garages have .
I am not aware of uneven tread wear like this being a particular problem on the Jazz. But you may have done more research than me. I dont for instance read sites that concentrate more on Hondas sporting heritage ,modifications, detailing etc. But AI probably does trawl these sites and may give a misleading result.
The Mk4 can deliver very high torque under acceleration so even those who believe they are driving 'sensibly' can wear out front tyres faster than rears . But wear is normally spread reasonably evenly across the tread width. But any car might have slightly more tread wear to the outer edge due to cornering forces. Maybe 0.5mm or so more tread wear on the outer edge of front wheels over the life of the tyre even 1mm or more in countries with lots of hairpin bends , mountain passes (the Netherlands Alps

) or 'enthusiastic' drivers. When I commuted to work I made a sharp U turn every day, sometimes quite rapidly to beat oncoming traffic . As a result I had slightly more wear just on the outer edge of the front nearside tyre tread than I did on the offside. (Not a Jazz)