There is no good solution for this.
I used to use the "AXIS T8705 Video Decoder" (which uses RTSP) - but Axis deprecated the product. The replacement product is not compatible with Meraki MV.
https://www.axis.com/products/axis-t8705-video-decoder
There is "Meraki Display" which you can run on an Apple TV.
https://documentation.meraki.com/MV/Viewing_Video/Meraki_Display_Introduction
BUT, it currently requires someone to actually log into the display each time it restarts. There has been talk about changing this so it automatically logs on on a power cycle, but I haven't head of anything being delivered in this space.
It is also only available via co-termination licencing, so if you are using PDL or something else you can't add the licence to the dashboard.
You could probably do something like using a tiny PC/NUC, and use a keyboard playback tool and have it open the web browser and log into the Meraki Vision portal and display a video wall.
https://documentation.meraki.com/MV/Viewing_Video/Vision_Portal%3A_Introduction