I just did a quick try :
In umg only an “editable textbox” and event “On text commited” set “on enter” to store the text. In level blueprint, create widget and add to viewport on begin play, enable mouse button (because i did this try in an opened tpp project) and event “p” to show array infos. It works (but you need to click outside of the box after each enter which needs to be fixed to be usable) A button event “On clicked” will be ok too.
Ideas to help you i have considering this :
Maybe your infos are not stored in your variables (try to print them on start to see and then check your input variables method and type).
Maybe your function is not set in the right place in your main graph.
Maybe your widget creation needs to be before or outside your function (not sure about that, but if things before don’t solve the issue this is what i would try.)
In hope it helps.