I'm not sure I'm up for an explanation covering different distro, but for my debians I have a pattern I prefer.
Look up systemctl for systemd distros, you can control it to the point it goes straight to the desktop. Without systemd, have fun. You need to unistall logon managers like Lightdm, and maybe plymouth.
You can simply uninstall all that and use the cli to logon and startx, is that the goal?
No operating system controls the initial display with splash or terminal output - that's a setting in your bios. At that point, no OS is loaded. Maybe this is what you mean? I think plymouth is standard now, it does something with this.
I set things for a real post, a real grub, then a luks passphrase - or a key - or nothing, then a desktop.