The apps by Rogue Amoeba on Mac are a great example of the trial model on Mac: https://www.rogueamoeba.com

I'm not affiliated with them, but I am a customer. They put a lot of effort into finding the right balance of what to unlock upfront in the trial. And their license/unlock process is pretty seamless.

I don't dispute the power of a free trial, but it can be a fair bit of work to get the details right.