might check out this topic i started, about using a minimal policy.
https://forum.rclone.org/t/in-some-cases-rclone-does-not-use-etag-to-verify-files/36095
but if you want the most minimal policy that can upload a file.
"Action": "s3:PutObject",
rclone copy d:\files\1GiB\1GiB.file zork: --s3-no-check-bucket --s3-no-head --s3-no-head-object --s3-chunk-size=256M -vv
DEBUG : Setting --config "C:\\data\\rclone\\rclone.conf" from environment variable RCLONE_CONFIG="C:\\data\\rclone\\rclone.conf"
DEBUG : rclone: Version "v1.62.2" starting with parameters ["C:\\data\\rclone\\rclone.exe" "copy" "d:\\files\\1GiB\\1GiB.file" "zork:" "--s3-no-check-bucket" "--s3-no-head" "--s3-no-head-object" "--s3-chunk-size=256M" "-vv" ]
DEBUG : Creating backend with remote "d:\\files\\1GiB\\1GiB.file"
DEBUG : Using config file from "C:\\data\\rclone\\rclone.conf"
DEBUG : fs cache: adding new entry for parent of "d:\\files\\1GiB\\1GiB.file", "//?/d:/files/1GiB"
DEBUG : Creating backend with remote "zork:"
DEBUG : Creating backend with remote "wasabi_zork_remote:zork"
DEBUG : wasabi_zork_remote: detected overridden config - adding "{d6Ro9}" suffix to name
DEBUG : Resolving service "s3" region "us-east-1"
DEBUG : fs cache: renaming cache item "wasabi_zork_remote:zork" to be canonical "wasabi_zork_remote{d6Ro9}:zork"
DEBUG : fs cache: renaming cache item "zork:" to be canonical "wasabi_zork_remote{d6Ro9}:zork"
DEBUG : 1GiB.file: Sizes differ (src 1073741824 vs dst 0)
DEBUG : 1GiB.file: multipart upload starting chunk 1 size 256Mi offset 0/1Gi
DEBUG : 1GiB.file: multipart upload starting chunk 2 size 256Mi offset 256Mi/1Gi
DEBUG : 1GiB.file: multipart upload starting chunk 3 size 256Mi offset 512Mi/1Gi
DEBUG : 1GiB.file: multipart upload starting chunk 4 size 256Mi offset 768Mi/1Gi
DEBUG : 1GiB.file: Multipart upload Etag: fb45c1c8b5eab382b93bec76f28907f2-4 OK
DEBUG : 1GiB.file: md5 = cd573cfaace07e7949bc0c46028904ff OK
INFO : 1GiB.file: Copied (replaced existing)
INFO :
Transferred: 1 GiB / 1 GiB, 100%, 42.082 MiB/s, ETA 0s
Transferred: 1 / 1, 100%
Elapsed time: 24.1s