Matrix still doesn't have a client with built in push to talk as far as I'm aware. The relevant issue on the Element github has been sat there for 8 years now

It does not seem like a serious project, at least not one being developed by folks who have user experience in mind

Same for multi-account support in Element Desktop. However: The new breed of clients (Element X) has this, along with many other improvements. This is probably what the happy user featured in the article was using. They recently (in the last few years) started to focus on UX, with what I would call some success.