The voice for my google assistant has changed since the weekend.
In the home app (and assistant) settings the correct voice is chosen, but my devices answer with a different voice. I have selected the British male voice but it answers with a US female.
I have retrained voice match in case that was the issue, but no difference.
Sorry to hear that the voice to your Google Assistant has changed, but I'm happy to help.
Please let me know if you have any further questions.