Back in 2018 I helped my buddy redo his kitchen cabinets and we spent a whole Saturday chasing the same problem, only we blamed the table saw blade first and bought a $90 Forrest thinking that was it. Turns out his fence was off by a hair at the far end and no blade on earth was gonna fix that. We finally checked it with a combo square against the miter slot and just stood there feeling dumb. Your stop block setup probably did more for you than the sled itself, because repeat cuts are where square really lives. The fingernail test is the honest one too, way better than eyeballing a gap and telling yourself it looks fine.