Looking at the database logs I see the following error:
2023-04-27 06:46:25.691 MST  ERROR: invalid input syntax for type double precision: " –3.87986"
2023-04-27 06:46:25.691 MST  CONTEXT: COPY yang2023, line 2, column dec: " –3.87986"
It looks like the space leading to the minus sign is confusing the parser. Is there a space in your CSV file?
If so, let us know if removing that space improve things.