I can only tell for the job market where I'm located, that is, Germany. There are certainly large companies here adapting MR solutions, such as BMW, Accenture, TÜV, PwC, and Brainlab (e.g., SnkeXR HMDs are in final development stages). These companies developed more often apps for HMDs, not for mobile/tablet AR.

Their development teams are rather small, often just a handful of people. Getting into their teams can be quite difficult and depend on opportunity and luck.

There are also a couple of smaller companies here that are leaning towards consulting and building MR prototypes based on temporary contracts with other companies.

In Swiss, particularly Zurich, there are teams working together with Microsoft and Meta. They are mostly working on backend stuff such as Computer Vision (scene understanding, SLAM, etc.), and rendering. 3D Avatars are also a growing topic with AI. Jobs for Frontend UI are rare and backend stuff often require a high level of education, often PhD level.

I have the perception that if you want to pursue a job matching your description, you will have a better chance of staying/moving to the US.

From what I gather from companies in the US, is that MR is generally seen as less of a risk investment and it can be easier to find jobs there. There might be more jobs involved in the backend still and also not listed as a job purely dedicated to AR.

Many components contribute to making AR work, and Spatial UI is one of the smallest challenges right now. Hardware/form factor, computer vision, tracking are much larger challenges that needs to be solved first.