The 428 is the number of albums on the curated list presented by Tidal. Your assumption is correct - the total is a lot more as evidenced by the excel list. I may have missed it, but I don’t think bulk import has been discussed.

James
NC1: 861v8, ID41, 218, 251(to outdoors), DSP8000SEUG, 7200SEC, DSP520 rears, Apple TV, DirecTV, Oppo BD103, QNAP251, Roon
NC2-M7005, Triad Silver Speakers,Acurus Amps

FL1: 861v4, ID40, 218, MS200, DSP8000SEs, DSP7200SEC, DSP5000s, DirecTv, AppleTv, OppoBD103, QNAP469, Roon
FL2: Marantz 7005, 251, M60s,60C,33s, Oppo BDP-93,MS200, Roon