Yes, S3 is extremely reliable and versioning protects against “oopsies.” I do always recommend disallowing s3:DeleteObjectVersion for all IAM roles, and/or as a bucket policy; manage old versions twith a lifecycle policy instead. This will protect against programmatic deletion by anybody except the root account.
I second these sensible protections. Also would recommend replicating your bucket as a DR measure. Ideally to another (infrequently used and separately secured) account. Even better if you do it to another region but I think another account is more important since the chances of your account getting owned is higher than amazon suffering a total region failure.
