Correction - they started investigating Manchester City in 2018.
For the period between 2008 and 2018.
It wasn’t until mid 2021 that reporters were even allowed to report on it:
https://www.dailymail.co.uk/sport/sportsnews/article-9821853/amp/The-day-Englands-senior-judges-dismantled-Man-Citys-plea-hide-Premier-League-investigation.html
And they didn’t bring the charges until mid 2023; well over a year ago, and the case still hasn’t concluded.
The investigation into Manchester City’s dealings since 2018 still hasn’t even started.