This depends on your ffmpeg version. AFAIK, libsvtav1 is available in ffmpeg 5.0.1
The current appimage is shipping ffmpeg 6.1.1, but it doesn’t appear to be built with SVT-AV1 support.
ffmpeg -codecs shows:
DEV.L. av1 Alliance for Open Media AV1 (decoders: libdav1d libaom-av1 av1 av1_cuvid av1_qsv) (encoders: libaom-av1 av1_nvenc av1_amf av1_vaapi)
Compared to the system ffmpeg 6.1.1 shipped with Debian 12:
DEV.L. av1 Alliance for Open Media AV1 (decoders: libdav1d libaom-av1 av1 av1_qsv) (encoders: libaom-av1 librav1e libsvtav1 av1_qsv av1_vaapi)