It is incredible how much the world has progressed in price/performance over the last four years. The Raspberry Pi B we first used had two cores, 256MB of memory and a bus limited to 100Mbps and used SD cards. Now for $75 you can get a Raspberry Pi 4 with 8GB of main memory, built in gigabit ethernet, wifi and bluetooth not to mention quad cores. And it can use POE so you can just power it from an Ethernet cable. Pretty amazing.
And there are new products like the Sispeed Maix Amigo using the new RISC V architecture for $39 with a touchscreen, camera and dual 400MHz cores plus some graphics as well and a battery power.
While many of these experiments can now be done with an Android phone, not being restricted to Kotlin is a big advantage.
For instance you can get like Raspberry Pi 4B with TFT Screen and case. This is on eBay but a pretty good idea. Only missing a camera and a battery.
The most exciting trend long term is that for modern devices things like k3s are coming that bring containers and other isolation to these devices. The big issue with them is how to keep them secure and robust while running all kinds of apps