They hired Berardi and then Souloukou. 2 CEOs. Perhaps your're counting Thiago Pinto, who wasn't a CEO.
Mourinho was overall a bad choice, but has lasted 2,5 years. They kept Fonseca, who hadn't been chosen by them, for an entire season, their first.
Pallotta did a great job until 2017-2018, then it took him just 2 years of bad decisions to ruin almost everything.
You're absolutely right regarding league placing, and it's what they working on. As for the stadium, they have canceled Pallotta's project (Tor di Valle), which couldn't progress anymore and started off from scratch with a new location (Pietralata). As of now, thry're close to where Pallotta's project stopped.