I tried to do this a while ago with a GNOME system, setting GDM to automatically log me in, but I ended up always getting prompted for my password from gnome-keyring shortly after logging in which seemed to defeat the point. If you use GNOME, you might want to look at ArchWiki’s gnome-keyring page which describes a couple solutions to this problem (under the PAM section) which should be applicable on any systemd distro.

Several Display Managers support auto login. For example :

• gdm : https://wiki.archlinux.org/title/GDM#Automatic_login
• lightdm : https://wiki.archlinux.org/title/LightDM#Enabling_autologin

I disabled the second login prompt on my KDE archlinux, since the LUKS one already pretty much authenticates me to my Laptop.

I have no clue which desktop environmen and session manager Nobara uses, but you can probably disable the login password somewhere in the settings.

On NixOS I did this:

services.displayManager.autoLogin = {
	enable = true;
	user = "kevincox";
};

# Avoid setting up a keyring every time I do a non-auto login.
# https://gitlab.gnome.org/GNOME/seahorse/-/issues/159
security.pam.services.login.enableGnomeKeyring = lib.mkForce false; 

Don’t automatically unencrypt. Auto login is fine though, but you’ll need to search for how to do it in your display manager. For example in sddm. If you have multiple users, use passwordless login instead.