Just recently updated to Bluefin 42 and figured out Tweaks is not integrated anymore.
One of the features of Tweaks is handling startup apps and scripts. I consider this feature critical, and even macOS and Windows comes with startup management out of the box. Ignition does that quite well, but these are only my impressions.
I believe Bluefin should follow suit and integrate Ignition as a system utility to handle what does start and what not, especially for the case of Flatpaks. This gives the user more control and easier fixes when something doesn’t start. In my case was Solaar that moved from a system app to a Flatpak, so the solaar command didn’t work.
This should complement the absent documentation about handling startup tasks without searching the Internet and opening the console.