@Derbychris
There was no need to install anything from other forums or playstore.
If you followed the link from "Boki_Srb" you would have found the TTS Engine Code Factory Vocalizer 3.4.3. (In your question about the English TTS)
With this app you can download the voices you need directly.
And disable Google Play Protect
But I suspect that you made a mistake in the TTS system settings
Addition:
I checked the English TTS post again, and it looks like you had the Vocalizer 3.4.3 crk installed?
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