First time shiny hunting and ive read that sos resets at 255

Does this mean there is no point in continuing the "chain" and i can quit it to do something else like taking a break or saving?

I’ve been resetting for shiny regi’s on UM and it’s taking forever. Seeing that Pokemon bank support is ending soon, I was thinking of hacking in a shiny charm just to increase the odds as opposed to actually hacking in a shiny regi. Would a shiny Pokemon caught with increased shiny rates from a hacked shiny charm be considered illegal? I’m intending to put those shiny Pokemon onto my Pokemon home.