Welcome to the community!
Did you know that you can customize chatgpt to a degree?
if you click top right, on your user icon
“customize chatgpt”
you’ll get this window
where you could enter your instructions so they’ll be remembered
One thing you can also consider doing is creating a custom gpt (these custom instructions are basicaly the same thing)
I don’t think so. It depends of course what you mean with effort, but if you mean that it’s basically muscle memory for the models at this point, then you’d probably be right. But if you already have a prompt (instruction) that can circumvent that behavior, putting it into these instruction boxes should get you 90% of the way there.