Sony has released an update to the PS5 home screen and set of menus that allow you to customise them (like a theme) to suit the styles and visuals of the PS1, PS2, PS3, and PS4 for the 30th anniversary of PlayStation. You'll be prompted to download a feature update when you next turn on your PS5, and then the console will restart to the classic PS1 bootup screen. You can then choose what system theming you'd like.
PS5 Home Screen Customisable with PS1, PS2, PS3, and PS4 Themes for the 30th Anniversary
Featuring the visuals and audio of each console