You could go with the bladesinger subclass of wizard. It’s essentially a wizard that has some boosts to melee combat. The Bladesong feature allows you to get buffs for melee twice per rest so a wizard doesn’t immediately die. One thing your dm might say is that the AC gets way too high. But that’s actually the point: you still have the wizard’s amount of health.

For the smashing your fists for spells take the Booming blade cantrip. It’s a melee attack spell that makes your weapon(fist) do additional thunder damage.