Ah, yeah, no I don’t have the ability to tune things out from any of my senses, unfortunately. I hear that lack is a pretty common complaint for autistic individuals, so it is what it is. I can’t relate to much of your described experience here. My memories are verbal descriptions or a vague recollection that’s immediately translated into words. No other senses get pulled into my memory or imagination. No reliving of experiences in even the most superficial of ways, which is often a blessing tbh. Probably why I’m heavy into living in the moment and for the future and don’t really care about sentimentality or tradition or whatever else people feel tied to the past about.

For me, there is no real nothingness in my head, ever afaik. Tinnitus yes, but there are always words. Closest is I taught myself to suppress the voice when reading because it’s much faster, but my mind is still occupied by words. “Daydreaming” is just thinking through how things work or could work, or ruminating on my anxieties. Like I spent half a road trip lost in thought about how to convert parking garages into hydroponic farms when privately-owned cars are disincentivized in the future. Just a literal monologue, in my own voice, working through what it would take and whether or not it’s worth the cost and effort to do. And that’s pretty standard filler when conversations die off (any talking instantly snaps me back, though).

My parents were kinda incredibly shit, and I was grounded from everything except books and breathing (this is much less hyperbolic than it sounds..) for literal years of my childhood, so I have strong doubts that it has anything to do with being bored. I’m sure there are ways to enhance your internal experience and extreme boredom might be one of them, but I don’t think you can outright change how it works in any meaningful way. You just got lucky like that, and that’s ok :)

FWIW tho I do have some idea of what it’s like to have internal visuals and stuff. I took some meds ages ago, which I definitely don’t recommend anyone take ever, that made my dreams permanently super vivid and largely internally consistent. Thing is, they are typically intensely mundane but negative emotionally-charged dreams where the only real indicator that tips you off to dreaming, unless looking for indicators, is the location. Since I have no other experience with seeing things that aren’t real, I have huge issues determining if things from dreams actually happened. My current strategy is assume it was a dream and wait for someone else to mention it, which they almost never do.