I know exactly what you mean because I went through the same thing after a recent update. The best place to find help is the official Tab Mix Plus site at https://tabmixplus.org/ right there. They have a dedicated troubleshooting section that walks you through creating a new testing profile, disabling extensions one by one, and even saving your browser console log to help identify conflicts. They also address the removal of the tab groups feature from Firefox and explain how Tab Mix Plus now handles it, including backing up your groups and saving them as bookmarks. The forum is very active and the developers are responsive, especially if you post detailed information like your OS, Firefox version, and a list of your extensions. If you want to get your tab management back on track, this is definitely the place to go.