Personally, I actually think retrocausality, once you twist your brain around it, is another perfectly sensible option that doesn't involve multiplying the universe into a near-infinity of inaccessible, unobservable parallels. The solution in my mind is that retrocausality actually isn't; what it means instead is that what "the present" is is even less like what you thought it was, and is even more of a partial order than relativity already told us it was. The answer to the "double-slit" experiment, to my mind, is that there simply isn't a "before" and "after" and some sort of "retrocausal self-interference" of the wave... the whole thing is simply one atomic event that doesn't have a before and an after, and your imposition of a temporal order on the events is much simplified from the reality. The mystery lies in your attempt to impose a global temporal order, which is appropriate enough at scale, onto a single local event where it doesn't apply in the way you expect. The results of the double-slit experiment itself is not that mysterious, merely counterintuitive, once you release the small scale from your imposed large-scale idea of how time flows.

It means that "the present" is actually quite complicated in a quantum universe with as many qubits as ours has, but, just as QM may be counterintuitive but eventually looks classical at a large enough scale, time may in fact be massively complicated but at scale it still works as we expect.