When I had this issue, it was fixed by disabling and removing the speech-dispatcher. Something to do with text to speech (I never use it but is sure to be a pain if you do need it) automatically doing things that corrupt the audio stream globally.
It does seem that way, however, in none of the AdaBoxes I've gotten from them have I had to sign up for their cloud services. That's where you think they would push it hard, but it just hasn't happened and I'm glad for that. There are usually a few samples that make use, but you always have the option to roll your own code on it and use their base libraries for interfacing with the hardware. It will be a sad (and probably disastrous) day when they bind their code to require cloud services especially considering some micros don't have wifi.
Neat. I'd love to see what that looks like (raytracer or cradle). Found an old Hack a Day from 2014 (https://hackaday.com/2014/11/25/ray-tracing-on-an-arduino/) where someone is raytracing on a 16Mhz micro. Should be faster on the 120Mhz portal, but it took almost 3 days :P
Adafruit offers a starter kit with a microcontroller, 64x32 led matrix, and some other doodads for ~$70 (https://www.adafruit.com/product/4812). It's really easy to tinker with. I made a clock that does some crappy visualizations and open sourced it here: https://github.com/kruffin/matrix_portal_gol It actually looks a lot like this Tidbyt (a box with a dot matrix).
The only thing it doesn't have is a RTC, so I just polled a time server every so often.
My favorite from that collection on map generation is by Herbert Wolverson: https://www.youtube.com/watch?v=TlLIOgWYVpI He goes over 5 or 6 different techniques that are easy to implement.
This may interest you; might not be what you were asking for. I haven't built one, but keep an eye on it and dream of free time to surface mount solder and poke around with it. The repo used to have a cost estimate and think it came out to around $100 but my memory may be fuzzy.
https://tqdev.com/2021-firefox-ubuntu-crackling-sound