Suggestions for the Admin Panel design

[Controlguyman (Train)]

I made a simple Admin Panel here:

It kinda looks too simple and basic.
I’m not really that good at designing UI. Any suggestions on improving this?

Any suggestions will be appreciated!

Pop-ups:

Speed version

[Bearlandonroblox]

you could try make something in this style

[levdasoalt2 (doesntexist)]

Maybe not so white and plain maybe a bit of a background and make the buttons different colors but the layout is decent.