Are you still happy with the Fluval 3.0?
Does it really not shimmer?
It shimmers very minimally, the extent depends on how much surface agitation you have as Andy has written. But it will never shimmer like crazy as those point source lights do.
I only noticed it for the first few minutes after I swapped from the tubes, after that it hasnt been visible to me unless I consciously try to see it. So I find it non-intrusive.
As for the Fluval 3.0 overall, which is not exactly what you asked but I think could be helpful, its a decent light. Not super powerful, and not the best spectrum for growing plants, but perfectly ok.
One of my pet peeves with it is that it will not turn on again after a power cut, so you have to manually turn the lights on through the app while you are in the same room. This is annoying especially if youre traveling away from the tank, and if you experience power cuts often, its something to keep in mind.
There are a lot more plant LED's on the market now, and you should look into Chihiros, Week Aqua and some of the other popular scaper lights before making your choice.
They are not rated as waterproof as Fluval 3.0 but they will give you a lot more light if you are gonna grow the most demanding plants. Some of them tend towards blurple (strongly red/blue coloration) and thats not everyone's cup of tea, especially not mine. But there are settings that can mitigate the impression somewhat. Other people hate the color rendition of Fluval, so its really down to personal taste 🤷♀️