For AGS bar (it's not a dock bar I guess), you should edit ~/.config/ags/widgets/bar/system.js.
Find "%H:%M" there and change it to what you like.
As for format, refer to this page.

The lockscreen is swaylock currently. Edit its config in ~/.config/swaylock/config to suit your needs.
For time format you need to adjust timestr, and the format is probably (? unsure) the same as the time on AGS bar.

For SDDM, I don't know.

EDIT: You may need to run man date as well for time format.

@clsty
I assumed it was somewhere in those locations, thanks for the tip. I found the sddm clock settings as well in my case /usr/share/sddm/themes/elarunMain.qml however I am still having an issue with logout not working from Hyprland it only goes to blackscreen with blinking cursor

it seem that /usr/lib/systemd/systemd-login is getting stuck when clicking logout or loginctl terminate-user XXXX if i go to tty3 and kill /usr/lib/systemd/systemd-login sddm shows up again.

update* logout works fine in lxde but logout from hyprland still freezes also changes to AGS bar did not remain...only lockscreen was success. The time in AGS bar is reverted back to 24h...EDIT* fixed it...there were multiple lines to edit date and time and all had to be changed. Still trying to figure out why logout freezes....

it seem that /usr/lib/systemd/systemd-login is getting stuck when clicking logout or loginctl terminate-user XXXX

Huh i though i fixed this some time ago.... It's an sddm skill issue. Changing that logout command to pkill Hyprland fixes it

@end-4 Thanks. Logout works by changing { App.closeWindow('session'); execAsync(['bash', '-c', 'systemctl terminate-user $USER ']) }); to { App.closeWindow('session'); execAsync(['bash', '-c', 'pkill Hyprland']) }); in "sessionscreen.js found in ~/.config/ags/widgets/session however terminate-user was working a few days ago? Not sure what happened?

I'm closing this issue since end-4 already switched to pkill Hyprland.

For time/date format, now you can directly configure it by editing ~/.config/ags/user_options.js. See Wiki.