How to get word boundary event to work on Android Chrome?

Hello Team,

I am trying to build a simple TTS app that converts TTS with highlight sync
using Webspeech API.  Here is a quick demo of what I built so far:
https://tinyurl.com/webspeech-demo

I am facing a couple of issues:

1. Since boundary events trigger only while using native voices, and as
select voice drop down in chrome lists all available voices, the
performance seems erratic to the user. Is there a way to list only native
voice on all browsers including chrome?

2. The boundary event does not work in chrome for android (I haven't tested
on other browsers as chrome for android is 'the target browser'). Is there
any way to get the boundary event to work on chrome for android?
It makes no sense to me to see that Google, which helped develop
webspeech api, has made sure that key features like boundary event triggers
do not work smoothly on their browsers. I understand that this could be
their way of making users switch to GCP TTS.

Can you please help me find a resolution to both the problems I had
mentioned?
Thank you in advance.

*KC*