“Reality is that which when you stop believing in it, it doesn't go away.”
(Philip K. Dick)

The existence of sentient beings (such as physicists) besides oneself can be treated as an instrumentally useful fiction – together with the rest of reality beyond one’s phenomenal mind. Mind-independent laboratory equipment is a convenient fiction too. The mathematical machinery of quantum mechanics is just a useful tool for generating empirically accurate measurement results within one’s phenomenal world-simulation.

In fairness, most “quantum Bayesians” (QBism) deny they are solipsists.
However, wavefunction realism has greater explanatory power than epistemic interpretations of the formalism – and even more so, wavefunction monism.