What I wanted to do:

ASUS@JOHN /m/d/Music> ffplay -f lavfi "amovie='02.\ Overworld.mp3'[in];[in]showcqt[out:v];[in]aresample=44100[out:a]"
ffplay version 2024-07-15-git-350146a1ea-full_build-www.gyan.dev Copyright (c) 2003-2024 the FFmpeg developers
  built with gcc 13.2.0 (Rev5, Built by MSYS2 project)
  configuration: (pruned)
  libavutil      59. 28.100 / 59. 28.100
  libavcodec     61. 10.100 / 61. 10.100
  libavformat    61.  5.101 / 61.  5.101
  libavdevice    61.  2.100 / 61.  2.100
  libavfilter    10.  2.102 / 10.  2.102
  libswscale      8.  2.100 /  8.  2.100
  libswresample   5.  2.100 /  5.  2.100
  libpostproc    58.  2.100 / 58.  2.100
[mp3 @ 00000154d71761c0] Estimating duration from bitrate, this may be inaccurate
[lavfi @ 00000154d7153340] Open inputs in the filtergraph are not acceptable
amovie='02.\ Overworld.mp3'[in];[in]showcqt[out:v];[in]aresample=44100[out:a]: Invalid argument

What I actually had to do:

ASUS@JOHN /m/d/Music> ffmpeg -v -8 -i 02.\ Overworld.mp3 -filter_complex "[0:a]showcqt[out]" -map "[out]" -map 0:a -c:v rawvideo -c:a pcm_f64le -f nut pipe: | ffplay -i pipe:
ffplay version 2024-07-15-git-350146a1ea-full_build-www.gyan.dev Copyright (c) 2003-2024 the FFmpeg developers
  built with gcc 13.2.0 (Rev5, Built by MSYS2 project)
  configuration: (pruned)
  libavutil      59. 28.100 / 59. 28.100
  libavcodec     61. 10.100 / 61. 10.100
  libavformat    61.  5.101 / 61.  5.101
  libavdevice    61.  2.100 / 61.  2.100
  libavfilter    10.  2.102 / 10.  2.102
  libswscale      8.  2.100 /  8.  2.100
  libswresample   5.  2.100 /  5.  2.100
  libpostproc    58.  2.100 / 58.  2.100
Input #0, nut, from 'pipe:':aq=    0KB vq=    0KB sq=    0B
  Metadata:
    TBPM            : 105
    encoded_by      : LAME in FL Studio 20
    date            : 2023
    encoder         : Lavf61.5.101
  Duration: N/A, start: 0.000000, bitrate: N/A
  Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 1920x1080, SAR 1:1 DAR 16:9, 25 tbr, 51200 tbn
      Metadata:
        encoder         : Lavc61.10.100 rawvideo
  Stream #0:1: Audio: pcm_f64le (PFD[64] / 0x40444650), 44100 Hz, 2 channels, dbl, 5644 kb/s
      Metadata:
        encoder         : Lavc61.10.100 pcm_f64le
  23.08 A-V: -0.016 fd=   6 aq=   18KB vq=18225KB sq=    0B

thanks ffmpeg