I have a bunch of games that wont stop after i exit them, they go in suspend and are not killable by command com (Powershell) with admin.rights, this is very anoying, i have to exit Playnite before they exit.
Can you give examples of games having this issue? I can't reproduce it myself and, by default, Playnite doesn't interact with the game processes in a way that could cause it.
Also, if you are using some custom Playnite plugins, then try disabling them to see if they are cause of the issue.