D&D 5E (2024) Using Action Surge to cast spells in 2024

[UngeheuerLich]

I think this very much depends on the RPG in question.

Nope.
I have never seen an RPG define everything.

Show me the RPG that tells you how often your character needs to use the bathroom or get penalties.
Tell me which RPG explains how children spring into existence.

Show me the RPG that explains gravity correcty, ballistc curves, correctly.

You can't have an RPG that perfectly explains the laws of biology or physics. It won't fit in any RPG book.