Where did he signal this?

Once you find the quote, go onto politco (a not exactly pro-trump site) fact-checking service to get the full context.

What full context am I missing?

Here from his own mouth https://youtube.com/shorts/DpVsZZtEpS8?feature=shared

And a proposed amendment to go with it, excluding Obama of course https://ogles.house.gov/media/press-releases/rep-ogles-propo...

Literally one guy proposed an amendment in an attempt to brown nose his boss.

It has practically zero support and has an actual zero chance of being ratified.

I actually agree with you, I don’t think a constitutional amendment will be ratified in my lifetime. But a lot of things I didn’t think I’d ever see have happened in the last two weeks

Time is not on his side.

With the best healthcare in the world available, I definitely won't be getting my hopes up on that. And furthermore the order of succession isn't much better.