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 their surroundings, and not transferring quantum information to them. One might call such systems "macroscopic", but with wide-eyed qualifications.
In view of your comment, I'd strongly recommend moving it to HSMSE.