I did see that, doesn't really help. Let me know if this works for you:
i) On Server ( S1 ) map the share ( \\Server (S3)\temp) with a user U1 credentials
ii) On server (S2), deploy simple SSIS package in SSIS catalogue on S1 which reads file from share pointing to S3 and writing back to a db on S1 and execute that package via t-sql ( SSMS) or any other app under user U1.
Most likely you will notice that even on S1 you have mapped a share under user U1 creds, you will not able to access the share with SSISDB catalogue even though u are executing the package as user U1, double hop issue.
I was looking for a way to map this share ( not drive ) before hand and be able to remotely access for U1. I have a work around, i am still trying to come up with better solution.