Experienced backend / server developer looking to pivot into engine work

I've been in the industry for 10 years now, doing a mixture of things for different teams but always with a slant towards the online domain - server-side, end-to-end feature delivery (engineering, I should add, with expertise in C/C++, C#, Java, etc.). I never had great opportunities to work in engine code, or when I did it was all proprietary.

Now I find myself looking for work after moving to support my wife, and roles all around me are asking for professional Unity experience. I've downloaded the engine, done many of the tutorials and made some of my own projects, but I question the best way to convince hiring managers and others that I've learned or know Unity.

One answer could be "make your own game", and I totally see how that could work, however I wonder about art asset quality (I'm a comp. sci. engineer, not an artist) in any delivered work I put out.

I saw that there's a certificate available, but also saw that the development community doesn't exactly respect it. Is there much value in online courses or trying to find local college ones that specialize in Unity as a tool (vs. learning C#, which I already know)?

I would welcome any feedback or suggestions. Thanks!