Does anyone have any advice on how to politely say "I like the company, I want to stay, but I don't like my current work and if it doesn't change for the better I'm going to leave in 6-months".
I once tried to say this as politely as possible, but I think I might have been too polite and tactful and they didn't understand. I had a date in mind, and had a conversation 6-months, 3-months, and 1-month before I left. When I announced my departure they tried to get me to stay.
You can just leave off the ultimatum and attempt to improve your situation by communicating it in a way that is directly actionable (I'd like to work on X instead of Y, can you arrange that?). You'll have your own internal deadlines of course, but you shouldn't communicate them.
It is the nuclear option, and you will lose the trust of your leadership chain.
if like many you switch jobs every few years you can never develop that reputation needed for an ulimatum in the first place. (Staying for years is never 100% in your power but some jobs have better chances of it)
Or maybe "I want to work on ____ new project, and my working this would be beneficial to the business because ____". But you have to have a real case for it and for why you are the right person for it
I try really hard but never understand where does this belief comes that you have to love your work.
The truth is some jobs suck so much that I refuse to do them long term, and other jobs suck but I can do them long term.
I once left a job after I was so stressed I got shingles, I believe it literally would have killed me had I stayed.