This applies only with jsmpeg app usage.

1 - Using a keyboard from a desktop computer, everything is ok.

2 - Using a keyboard from an Android tablet, the contents of the keyboard is sent when you press the -> on screen key, and so everything is ok.

3 - But when using the on-screen keyboard on iPad, only the first character is sent.  This is likely a bug with jsmpeg. On iOS, I have reproduced this bug with Chrome, Safari, Brave.

I've made a short video demonstrating the problem:
https://youtu.be/edR3lNi8zDM

Nothing I can do on this since I have no iPad for testing.

However, please try out changing the "macLike" variable
in .../SDL2/src/video/jsmpeg/data/jsmpg-vnc.js to not
contain the "iPhone|iPod|iPad" strings in the regexp.
Maybe this helps.

Am I correct in understanding that I need to build my own Androwish in order to test this suggestion, as the file you suggest editing is bundled inside it. Is that right?

Yes and/or no. The quickest result is to use a hex editor of your
choice, search for "iPod" which should give exactly one hit (for the
windows binaries, MacOS not verified) and then edit the regexp from
"iPhone|iPod|iPad" to e.g. "yPhone|yPod|yPad" or another letter of
choice.

Perform this on the undroidwish.exe or the undroidwish binary contained
in the MacOS .dmg. And, yes, code signing is for wimps, indeed ;-)

I did the HEX edit as you suggested, but did not perceive a difference in functionality.

A few people have made Wish-based virtual keyboards, such as:
https://wiki.tcl-lang.org/page/Keyboard+widget

and that seems like the obvious work-around.

Though, I presume that since this bug in someone else's Javascript code (you didn't write it) it's also possible that a later version of their code will fix this minor problem.

Meanwhile I was able to reproduce the problem with Safari on a Macbook.
A possible fix is in check-in [2e89a99e47]. Please check this with the
updated undroidwishes which are ready for download in the usual location.