Hi @vix ,
said that to obtain an acceptable solution for my case I’ve worked by tries because I have poor knowledge about the subject,
Jeremias is right: you have to play with the After dependencies of plymouth-quit.service.
In my case I added ‘wayland-app-launch.service’ in the After dependencies of plymouth-quit.service to obtain the splash screen onscreen until the wayland/weston block launch my dedicated Qt app and then removed ‘plymouth-quit-wait.service’ from the After dependencies of weston.service to obtain the blanking of the splashscreen before my Qt app launches.
That is enough for me.
In your case, better, I think that if you create a service that start after the last part of the docker launch block and set a After dependency into plymouth-quit.service related to that just created service, the splahscreen remains onscreen exactly until your containers are up and running.
Hope to help,
Pipe