Boundaries are healthy limits set to protect oneself, while ultimatums are demands that pressure others to change, often with a threat.

Boundaries respect both parties. Ultimatums prioritize one’s own needs.

Using the meme as an example, "if you don't stop playing video games I'm leaving" is an ultimatum, putting herself first. It neglects the fact that he enjoys playing video games, and forces him to choose between her or his hobbies.

"I feel neglected when you play video games so much instead of spending time with me, what can we do to find something that works for both of us. If we can't find a solution, I worry about the sustainability of our relationship" would express her feelings, identify his behavior that is causing those feelings, and respect the fact that his hobbies are important to him and give him space to continue enjoying them. And the boundary is "if we can't work together on this, this relationship won't work".

There is nothing in what I said that suggests connotation or social acceptance are a factor - polyamory exists, couples could enjoy drugs together, and money is important to everyone. What you listed are your boundaries, and that's cool - I have the same ones. But they're not universal (though definitely some of the most common). What matters is how they are communicated.