Is it possible to have a profitable site using Googles Ads only?

Yes, and I have one. Does about 7K per month and has been doing so for over 2.5 years.

All you need is a niche topic, lots of content and possibly great knowledge of SEO.

I keep seeing comments from folks here indicating it's possible.

I've had nearly 50 over the last 15 years and have only ever spent money on Google Ads

I think it all boils down to what the function of the website is. In my case most of the sites were e-commerce so having ads was more detrimental. If your site basically runs itself and you're not selling a product, service, or trying to flip the site I'm guessing ads are probably one of the few ways to be profitable.