I haven't played SC, and i haven't played Eve in a while, but here is some readily available information:

1. Eve has been in release state for 20 years.
2. Eve has an ancient dedicated player base that probably knows the game better than the devs.
3. Most old players place a priority on helping new players and keeping the game healthy.
4. You can't walk around outside your ship.

In Eve, you control your ship in a 3D view more akin to a strategy game. In SC you pilot it from the cockpit like say Elite Dangerous or other space sims.

Eve Online is much much more strategy (third-person) and diplomacy. You don't get anywhere without getting involved deeply with other player groups (corporations). It's more of a business sim than a space sim.

SC is much more pew pew and first-person and teamwork will be much more casual.

Star Citizen is all about first-person perspective. You're not a "capsuleer" like in Eve, you do exist outside of your ship, you can walk its interiors, you can walk cities, socialize with people on the ground, or capture enemy ships and go ground battles, you go to planetary "hotels" to rest, etc. etc. It's more like an immersive space sim in a massively multiplayer world - it's about living in this virtual place. If we would use all those fancy modern buzzwords, "metaverse" would probably be the closest.

Eve operates on a very different layer of abstraction. You don't even get to directly control your ship - you set general commands for where and how it should move to target, orbit it, etc. (which is something that frustrated many newcomers since this model is pretty much nonexistent in modern space games). The juice of Eve is not personal interaction of character models, which doesn't exist, but the economy and legacy of such a massive project. When it comes to an economic system, Eve may rival the real world in its complexity. Also, the control of systems adds a strong political layer on top - something that players expand on, creating a long and complicated, player-generated political lore. People there take it very seriously, which makes Eve more of a strategy than the game you immerse yourself in to have a light and nice evening.