This is what I found. A few articles from 2016 and on.
Opinion | Michelle Obama for President in 2020
There has also been speculation Mrs Obama would herself run for office.
Then starting in 2023, a bunch of stories initiating with the gossip rag RadarOnline. Example:
8-11-23
Michelle Obama vs. Donald Trump in 2024?
radaronline.com
8-22-23 https://radaronline.com/p/michelle-...retly-testing-barack-wife-joe-biden-concerns/
Followed by a flood of articles from the NY Post, a Rupert Murdoch (conservative) rag. Here are a few, I have more links if you want to see them.
“I am terrified about what could possibly happen because our leaders matter, who we select, who speaks for us, who holds that bully pulpit,” Obama said.
nypost.com
“There’s no question she’s more talented than Joe Biden is politically. No question,” Kelly said.
nypost.com
Former first lady Michelle Obama may be looking to step into the 2024 presidential race, according to Post columnist Cindy Adams.
nypost.com
Obama’s wife is scratching to maybe be our next president. Her husband’s helping. Pay attention.
nypost.com
“Biden has dementia. I mean, I knew this to be true,” O’Reilly claimed during a segment of his “No Spin News” podcast from Monday.
nypost.com
On Jan. 30,
RadarOnline.com published an article with the headline, "Michelle and Barack Obama Secretly Plotting Her Presidential Run to Force Joe Biden Out of Race, Shocking Report Claims."
"As its source, RadarOnline.com cited reporting from a New York Post opinion article. The headline of the Post's article specifically used the word "may," as in, "Michelle Obama may already be working on a 2024 White House bid." The body of the story also used the word "reportedly" and cited a source who purportedly informed the Post of the news from other "credible sources":
In other words, RadarOnline.com published an article about the rumor and mainly cited an opinion piece from the Post. In the Post's article, the author cited an unnamed source. That unnamed source purportedly claimed to have inside information from other sources."
Here's everything we know about the rumor the Obamas were attempting to make a return to 1600 Pennsylvania Avenue.
www.snopes.com
Sure looks to me like all this talk about Michelle is coming from the right, not the left.