Straight from the Google Horse’s Mouth on Play Store apps not running on Chromebooks: I can’t download apps from the Play Store on my Chromebook - Google Play Help
I think as long as My Phonak can run on Android tablets and the latest Android version on a Fire tablet is not too forked a version of Android, My Phonak is very likely to run. A Chromebook is not an Android device, a Fire tablet is and the How to Geek article implies in the very first paragraph: “That means, that you can install the Play Store and gain access to millions of Android apps and games, including Google apps like Gmail, Chrome, Google Maps, and more.” I don’t think that they would make such an unqualified statement unless there are very few exceptions but hopefully gfmucci is going to provide us an answer in a few days! I’ve used BlueStacks on Windows 10 in the past and run apps from both the Google Play Store and from the Amazon Store under Win10. In fact, for one, I think I bought the “Pro” license in the Amazon Store but have downloaded the app itself from the Google Play Store and used the Amazon version of my license to upgrade the app from the Play Store (because the “Pro” license unlocks a DEVELOPER upgrade feature contained in either store version of the app). And like the Fire Tablet, BlueStacks is some forked version of Android, AFAIK. Although looking now (it’s been years), I see that BlueStacks lets you choose a version of Android for app compatibility - and is only up to about Android 9: BlueStacks 4: Why does BlueStacks recommend a specific Android version for some apps? – BlueStacks Support My Phonak only says that it requires Android 7 and up. According to this: Identifying Fire Tablet Devices | Fire Tablets (amazon.com), the latest Fire Tablets run Android 9, API level 28.
Here’s what My Phonak product support says what’s required: Phonak product support | Compatibility
BT 4.2 and Android 7 (or higher)
The latest 2021 Fire HD tablet has BT 5.0 (and presumably Android v9)
Edit_Update: Interesting that Phonak says that My Phonak only requires Android 7 (or higher). Android 7 would appear to be too low an API level (Android version) for the current Google Play Store. Android 7.x is only API level 24 or 25. Android Developers Blog: Expanding target API level requirements in 2019 (googleblog.com) and | Android Developers API LEVELS
Since November 2018, all app updates on Google Play have been required to target API level 26 (Android 8.0) or higher. Thanks to the efforts of thousands of app developers, Android users now enjoy more apps using modern APIs than ever before, bringing significant security and privacy benefits.