Storing mutable arrays in flash

Hey there! Making this post separately from my other post so it's easier to find in search.

I'm working on a project that stores an array of 572-byte-long Uint8Arrays in RAM, like so:

var arrays = [];
arrays.push(new Uint8Array(572));

These sub-arrays are then read and written on the individual byte level. They're also not supposed to be read or written to extremely often, just maybe a couple dozen times a day.

It's my understanding that this nested array is stored in RAM. However, I have a lot more free flash storage space on my Puck than I have free RAM. Is there any way to implement this same functionality (reading and writing individual bytes) while using the much larger flash storage?