Text-To-Speech Broken in Samsung One UI6

I have a class set of Samsung Galaxy Tab A7 Lites in my classroom. I've had them for around 2 years or so. I didn't teach the class that used them last year, so I had a lot of updating to do to start the school year off. At the moment, everything in MIT AI2 Companion works except for Text-To-Speech, which appears to be broken.

Here's what I've done so far...
-- I tested multiple apps on my phone and then the same apps on several tablets.
-- All other app components functioned correctly (except Text-To-Speech) including other audio functions which worked normally... this includes tablet defaults (like the clicking sound when a button is pressed) and app-specific functions (playback of audio files).
-- One tablet worked correctly with Text-To-Speech...
-- -- Going through the tablet's settings, I realized that the working tablet was on Samsung One UI 6.0.
-- -- Non-functioning TTS tablets were on Samsung One UI 6.1.
-- When I got our school's IT tech involved, he upgraded the tablet to UI 6.1, and the TTS promptly stopped working.

Does anyone have a solution?
Could somebody from MIT AI possibly do an update to correct it if the cause is found?

Thanks in advance for any assistance.

You could try this pre-release version of the companion app:

To complete the experiment, try a built app too, to rule out total loss of that component.

Thanks for the quick ideas, but...
-- I tried 2.72d4 on one of the tablets and got the same result: sounds, but no TTS (and no error messages with either companion app build).
-- Afterward, I immediately tested the same app again on my phone and it worked.

For the record, my phone (which worked) is a Samsung Note20 Ultra 5G and is on UI 5.1.

Try finishing the code work first and then maybe try to build an APK [ installing the app] and then testing it. It won't take a lot of time to download an app.

I have the same UI and it works just fine in companion.

Default settings.

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Any specific language you are using?