We have been using Ash at work for the past nine months. Our experience has been brutal. Learning curve is absurdly steep. Macros everywhere means you have to trawl through documentation to find information about the exact thing you're trying to do, and often cannot. Every time you step out of the well-trodden path you're punished with cryptic errors, for which there's nearly nothing on the web, and AI tools are clueless about. So your only option is to post about it in the Ash discord (which is for some reason not part of the official Elixir discord) and hope that someone responds before you lose your mind.
The only thing it has done for us is that our data layer has started to look somewhat standardized. This may be a reasonable benefit for larger teams that don't have any code quality or architecture discipline. For small teams though, and especially for solo projects, I wouldn't recommend it. Your productivity will suffer.