is it possible to use 24h timestamp for chart?
Changing the Hour format in the Visualization preferences on your account settings should change that. But I tested here and it seems to not work on developers account.
TagoIO is already handling this, but I recommend you to open a ticket support so you can be notified when the issue is fixed.
I have 24h Hour format in the Visualization preferences but no effect to charts…
We are working to use the same time format of the account preferences on the chart.
It would be best to open a ticket through the support page on Admin, that way you would get notified when the feature is deployed!