Can an install script be made to install a game from a site to your Steam library?

I noticed when installing the Decky-loader plugin on Steam Deck that you can basically just copy-paste a "curl" command into the terminal and that will neatly add it into the Deck interface.

Can you do something similar, but for a whole game? The game I had in mind is one where you download the installer from a site, add some patch files, and change the game's target location in Steam to the newly generated exe file. It's a bit of an involved process to do purely through Steam because of the installer, so it's a bit difficult for people trying to correctly install the game on a Steam Deck.

I was just looking for any way to make the process easier for anyone to easily install the game correctly through Steam without using extra stuff like Lutris. Ideally something that can be copy-pasted into the terminal to take care of basically everything, but I'm guessing that's too optimistic.

Does any sort of option like that exist?