Yeah and thats the direction I might go. But the raspberry pi pico is a nice in between because it has enough ram (264k) and rom (2mb) to do this, but not sure if it could handle tilengine (sounds like you would need a SDL driver specifically for it).
In practical terms, the cost of a PI zero is not a significant blocker. I just dont like the idea of having to run linux in order to run something retro... :)