Suarez is a born goalscorer, it's in his nature to first look for a goal rather than pass. Dembele on the other hand is more of a creator so it's understandable if he'll first look to pass rather than score. They are just different type of players so they will often take different decisions in similar situations. Sometimes their decisions will turn out good, other times bad but I don't think we can call either one of them as more egoistic/less team player based on those decisions.
Even Messi sometimes decides to take a shot (especially in close games when we're struggling and he feels the need to decide the game) when it would be maybe better to pass. Not often but it happens. (Occasional) poor decisions don't make players egoistic.
And when talking about big egos I usually think about players who put their own interest in front of team goals. I don't think we have a player with that kind of personality in current team. Luckily we have strong enough locker room with veteran leadership so even players who come here with some of those traits (like Neymar) eventually have to adapt or leave if they can't.
We'll see what happens when all veteran homegrown leaders (Iniesta, Messi, Busi, Pique,...) will leave/retire because they are big part of the locker room stability even in tough times and they help newcomer's feets to stay on the ground. Outside Roberto I currently don't see La Masia player who could take over their leadership role in 3-5 years so foreigners like MATS, Umtiti, Coutinho will probably have to be the one to keep locker room together.
That's why I believe we should develop Dembele not only on the pitch but also off the pitch so maybe in time he could also become one of the team leaders while at the same time being 4-5 years younger than most before mentioned. Maybe he doesn't have personality to ever become a team leader so we'll only have a good/potentially great player and I'll take that as well as long as he'll stay professional and his actions won't hurt the team. But after all money invested in him we should now also take time to try and help developing him. At the end it's all up to Dembele but he has a lot of examples in the team to learn how to handle his career professionally on and of the field.