This popular review reminds you that even a small bug (or a paperclip!) of about 1 g and 1 cm has a wavefunction decohering in $10^{-23}$ seconds. The TDSE works fine, it is just not informative for it for longer.
That review will remind you there are, nevertheless, "large" systems, cryogenic Weber bars of over a ton, superconducting Josephson junctions, ..., which checkmate decoherence by suitably isolating themselves from the environmenttheir surroundings, and not transferring quantum information to them. One might call themsuch systems "macroscopic", but with wide-eyed qualifications.
In view of your comment, I'd strongly recommend moving it to HSMSE.