Yeah, if you want to play a caster, the first thing you should do is figure out WHY you want to play a caster. That should inform you on what role you'll be filling in the group, and that will inform you on what spells you should take.
Also, outside of a couple spells being completely worthless (like true strike), they all generally have their moments. Some are a bit more situational and may only come into play a handful of times, but it's GREAT when you finally get to use one of those spells, especially because a lot of DM's don't usually plan for some of the more obscure spells.
And as far as eldritch blast goes, it's really only OP for warlocks and that's if they build their entire character around it, which makes for a pretty boring character that basically just does the same thing every round. For any other class, eldritch blast and firebolt are mostly the same (mechanically, eldritch blast will do more consistent damage due to each ray being its own roll, as well as being a damage type that is much less likely to be resisted). I think a lot of people get blinded by how well warlocks function with eldritch blast and end up wasting feats on getting eldritch blast on a non-warlock, without realizing that it's the invocations that REALLY make eldritch blast shine.
But I digress. Figure out what you want to do and build your spellbook towards that. If you want to be a blaster and just nuke people, sorcerer's can do well at since their metamagic allows them to break the rules of spellcasting (quicken or twin spell let's them cast more than one spell per turn, empower let's them reroll damage dice if you get a bunch of 1's and 2's, etc) as well as flexible casting letting them regain spells lots with a bonus action. BUT they have limited known spells so they aren't very flexible in what they can do in any given moment.
Thing about damage though, is that basically everyone can do damage and unless you're fighting a large group, most other classes can do reliable, high single target damage. Casters really shine with AoE (just take fireball and move on lol) and controlling the battlefield.
But really, don't worry about what the internet says on spells unless you are playing some ruthless min/max meat grinder game. People spend A LOT of time with spreadsheets and sims and preach the results like gospel, but that doesn't really allow for personal creativity and role playing. My current game I'm playing a triton storm sorcerer and while on paper, storm sorcs are one of the weaker subclasses, I'm having a blast finding good uses for lame spells like gust of wind (I've pushed SO MANY creatures off cliffs, I love it)