I had the same problem on Samsung, first Flip 4 then S24 Ultra. I solved it with these steep:
-selected the tts voice I went to save to check the system.ini file in the following section:
[regional]
default_voice_dir_name="voice/iGO LUNA TTS_Ita.zip"
default_voice_engine_capabilities="|,default,can_play_loc_string,1,engine_name,android,language_name,ces-CZE,speaker_name,N/A"
default_voice_id="3641"

I then noticed that the language in "android,language_name,ces-CZE" was not in fact Italian, despite being selected.

-I then inserted the correct strings in the sys.zip/plugin:
[regional]
default_voice_dir_name="voice/iGO LUNA TTS_Ita.zip"
default_voice_engine_capabilities="|,default,can_play_loc_string,1,engine_name,android,language_name,ita-ITA,speaker_name,N/A"
default_voice_id="3641"
default_voice_key="TTS_android_ita_Gg"

Obviously you will have to check and insert the correct strings for your language

This trick worked for me...