Overall Settings

[ozgarek]

It gets quite annoying when you a game for the first time, and it instantly sets it resolution to be tiny. Now, I get that this is for lower-end PC's, but I think an option inside of "In-game settings" where you could set your default options for games would be a nice quality-of-life change, that way you don't have to constantly change settings for each game you play.
(I know this is normally a problem for older games, but a lot of people like me like to play the classics.)

[Crazy Tiger]

Steam isn't integrated into games in such a way, it's also rather impossible to do as games offer different options. You can only set in-game settings in the game itself.

[Cathulhu]

Not to mention that people have different tastes for how their games should run.
While some are fun with 30FPS, many want 60FPS at least if not 120/144Hz.

Most games these days automatically use the desktop resolution when starting the first time, so your suggestion only applies to older games and is a not much of an issue anymore.

[nullable]

Not to mention games don't have universal configuration schemes, so kinda hard to manage them universally.