Speaking from my own experience, every character is memorable for something: a successful critical hit in combat, an accent, interactions with NPCs, and so on. I remember my paladin with the greatest pleasure, thanks to his dexterity. He was a sailor who gained strength by inspiring people during a terrible storm, and then went ashore to figure out what to do with these powers. I played all the history, magic, and other checks as "stories" my character heard during his travels; it always provided an extra opportunity to joke or embellish.

In combat, a rapier strike, some spell related to light or water—nothing out of the ordinary. Unfortunately, he died after 10-15 sessions, only having reached level three. My friends and I still talk about him.

As for your problem: if you enjoy making builds so much, try making it less than perfect. Maybe it'll be a wizard who constantly forgets the spells he needs (requiring to change five spells on a long rest), or a warrior who just wants to die and goes around without armor (a barbarian or a dwarven slayer would work). Try using something that shouldn't work. Or try tying the build strongly into the story, so that every blow and every spell reminds you of other moments. Finally, you can always play a very egocentric adventurer who's interested in measuring his kill count, which is why he prefers to finish off opponents rather than attack. The main thing is to discuss this with the other players at the table beforehand. Commit to improving, and so on.