I feel like maybe locking into a certain size would help with the sudden jumps, too; let’s say things are locked into the aspect ratio of the canvas; things would maybe “look” clearer, with the jumps being less of a flashbang (watching the above timelapse hurt my eyes a bit; I imagine more seizure-prone/vision-sensitive folk would have a worse time than me).
(AKA I’m not against just setting a bg color, but I feel like that could still be a very specific can of worms when it comes to accessibility)