Saturn V was less powerful than SLS - but it could send an entire mission in a single launch. Capsule, lander and all.
A lot of what NASA has been doing with SLS is just trying to... rationalize its existence. This is what gave us NRHO, Gateway and others.
Reportedly, some of the people at NASA just believe that having an inefficient, wasteful and corrupt space program is better than not having it.
That's just not true. Saturn V had a paylod of 43,500kg to TLI. Only the largest configuration of SLS(Block 2) exceeds that with 46000kg. A Falcon Heavy is far below that.
My point stands though: no Artemis mission has plans to launch a full Apollo style capsule + lander stack. Artemis HLS, SpaceX and Blue Origin versions both, flies entirely on its own. So what's required of both SLS and any would-be SLS replacement is a far less demanding mission than what Saturn V has done in the past.
Which calls into question: what SLS is even for? Does it add value to the mission, or is the mission subtracted from to justify adding SLS to it?