A few settings you may wish to consider for your firefox’s about:config page.
browser.ml.chat.enabled = false
browser.ml.chat.shortcuts = false
browser.ml.chat.shortcuts.custom = false
browser.ml.chat.sidebar = false
browser.ml.enable = false
browser.tabs.groups.smart.enabled = false
Which are the relevant platform(s) and version here? I don’t seem to have the .chat variables.
With Firefox on Android I only had:
browser.ml.enable = false
Firefox 141.0.3 (Build# 2016106991)