Don’t play casters. They’re annoying. Use the magic hybrids like arcane trickster or eldrich knight. You get just the combos that you need without worrying about versatility. When you pick a character for a fighting game who wears zero armor, you really have to think about what justifies that obvious disadvantage.
That only works right now while the 18 int circlet holds, though. Once that effectiveness fades and your attack rolls start to decline, these hybrid classes will start suffering.
I'm not sure if the 18 int circlet's effectiveness will fade for hybrid classes.
Eldritch Knights and Arcane Tricksters get 4 ASIs by level 12. Assuming they spend 1 of them on a feat, that leaves 3 actual ASIs.
A fighter would probably use 2 of those ASIs increasing STR to 20 and a rogue would do the same for DEX. This leaves 1 ASI for something else, which is not enough to improve Intelligence to 20.
The best bet is probably to keep the Arcane Circlet and use that 4th ASI for a feat or increasing Con or Wis.
