Files with zxs extension are associated with a zx32 snapshot format.
ZXS file extension - ZX Spectrum emulator ZX32 snapshot file
What is zxs file? How to open zxs files?
File type specification:
The zxs file extension is related to a snapshot format used by zx32; .ZXS 'snapshots' can also contain tape and disk images, but are unrelated to the ZXS tape format.