The ones that are easiest to point to are turns of phrase like “living your best life”, “that feeling when you…”, etc.

I don't think the LLMs are to blame here. Not yet, at least.

This is caused by people active in English-speaking communities translating memes literally and spreading them in their native language communities as-is.

As the meme spreads, monolingual speakers begin using the same format and eventually they reference it off-line.