It could be that the reason for this error is Python 3.8. At least if you have not taken any action to make snappy work Python 3.8.
There is a guide on how to use sen-et. It might help you.
Technical Review of USER MANUAL FOR SEN_ALL_S2_S3_05032022_final.pdf
There is post which mentions the necessary steps to use snappy with Python 3.8.