GURPS can create characters in any type of setting that would be sufficiently detailed and nuanced to be novel protagonists *IF YOU WANT TO GO TO THAT LEVEL OF DETAIL, WHICH YOU DON'T HAVE TO*. You can also whip up the equivalent of a D&D hireling in a few minutes using a template or a simplified form of character creation. Its default rules produce a high degree of verisimilitude, so that your game can produce results that seem realistic at a glance (given the constraints of the game world). You can fine-tune those rules to produce more cinematic/unrealistic results, or more realistic(ish) results, albeit at the cost of added complexity.
Its core mechanics are not really complicated (90 % of actions are resolved by rolling 3d6 and hoping for a result below your relevant skill level, plus or minus situational modifiers), but character creation can be intimidating if your GM doesn't curate the list of available traits, advantages, disadvantages, powers, etc. Once characters are created, it's a rules-medium game at most unless you use optional systems to add more details to combat, in which case it can go quite crunchy and detailed.
Beyond the genre-neutral character creation and basic rules, there are lots and lots of supplements that provide specific and optional rules add-ons for various types of games, i.e. spaceship creation and combat, realm management, social engineering, mass combat. This helps give campaigns featuring those aspects a more "bespoke" feel, albeit again at the cost of increased rules complexity. Running games with too many "subsystems" attached would probably be very unwieldy, and unfortunately there does not seem to be a well-developed technological framework to aid running such games.
I like GURPS, but it's not an easy game to propose to new players and setting up campaigns can be a lot of work if you want some of the more detailed rules options.