Unity doesn't dogfood their own engine. Unity does not develop any games themselves. This is completely unlike Unreal, who has always released games using their own engine. Unity doesn't do it, and it shows.
Unity has a handful of features that either barely work or only work in some contrived prototype case. They still have 3 different rendering pipelines without clear direction on which you should use.
They have this whole new game architecture (DOTS) but it seems like you should not use it. It's just there to confuse you.
They have a new GUI coming soon? Maybe?
Mobile builds are a complete clusterfuck with all the native code plugins you have to integrate. As soon as you get a few native code plugins (which every serious mobile game does), it takes several days of messing with your build pipeline to make things build properly on iOS and Android. And then you have to do it all over again every year to keep up with platform changes.
They've also released a ton of plugins and features for AAA games and cinematics that are completely useless to indie devs and mobile devs. I would love to know what their revenue split looks like between mobile, AAA, indie, and everything else. From my perspective, they haven't done much the past 3 years to make mobile dev & indie dev better.
Still no good webGL export if you care at all about load times. I'm not sure if they have just given up on this or what.
The Unity Editor also just has weird problems sometimes. It gets exponentially worse if you have large projects too. This is why Unity never sees these problems because they only work with small prototypes. They have no "real" projects which can easily get into the 50+ gigabytes range. At that size of a project, you start to have more weird issues.
Unity is still (usually) the best choice for mobile and indie, but man I wish they would just spend the time to make their own mobile game, see the many pain points, and fix them.
I will say, they did create and release the Addressables system, which is a big improvement for resource loading on mobile. Also their acquisition of TextMeshPro and support of that plugin for rendering text, super good. Their shader graph editor is still WIP and tied into their rendering pipeline mess. Nested prefabs are also a huge improvement.
If I was Unity, I would setup 2 internal game teams. One team building PC & console games, another team building mobile games. Build real games, release them on the app stores, and keep them updated for 2 years. Who cares if they don't make any money, that isn't the point. This is a realistic usage of the engine and it would expose problems that Unity doesn't seem to know about.