Not quite sure I understand what your issue is, since there are several different fan control options which work well with smartthings and then will also work with either Echo or Google home. You don’t need to use echo as an intermediary.
Have you had a chance to look at the fan control FAQ? Although it says “Alexa“ in the topic title, it would also work with Google home.
FAQ: 2019 Ceiling Fan and Dimmer light wall mount control compatible with SmartThings and Alexa?
As far as echo versus google home, both work well for a voice control. If you are already heavily invested in chromecast and other Google systems, you may like Google home better. Otherwise as far as home automation goes at the present time echo offers some features, in particular much better routines, which are a somewhat better fit. They definitely make integration with non-smartthings controlLed devices easier than if you were just using Google home.
FAQ: Can I trigger an Echo Action without Speaking to It?
But there are plenty of people using each, it’s just a matter of personal preference. Choice is good. 