In 2024, getting to cast two fireballs on the same turn isn't TOO hard. You just need to be a thief with a necklace of fireballs. Fast Hands lets you use the Magic action as a bonus action, so you use that bonus action to chuck a bead from the necklace...and then do it again with your action.
Pew pew, boom boom.
The necklace of fireballs works around most limitations since you don't actually cast a spell from it. It just produces an effect that is like a spell. So it doesn't need to respect spellcasting limitations.
FWIW, you could also be a sorcerer who uses Quicken Spell to cast Fireball and then also use a fireball from a necklace of fireballs - potentially more effective, since you can upscale your fireball, if you want. But a little less funny, because you don't expect your rogue to become your fireball artillery because of a serendipitous rules interaction.
Pretty niche, I guess, and consumes a lot of a rare magic item, but probably worth the 4k gp when you get the chance if you're a thief or a sorc...