Hello @DBUser2,
The COPY INTO command does not have a specific documented limit on the size of the data or the number of files that can be ingested at a time. Timeout errors can occur due to network issues, resource limitations, or long-running operations. Are you running the commands on a warehouse or over notebook?
Looking at cluster/warehouse metrics would be a good way to start investigating.
Also, do you have the statementID is executed via warehouse?