I don’t have it set up myself, but after running into issues making it work with Synology software I came across the reason and also a workaround someone mentioned for duplicati which unfortunately doesn’t work for Synology. The reason is that Amazon uses DNS to resolve the location if buckets. This is not how it works with the gateway. You can disable this in duplicati by adding the option s3-ext-forcepathstyle=true
Now if only I could find a fix for Synology cloud sync to work around this as well… I hope it will help you at least.
Edit: if this doesn’t work or you need more info, googling for tardigrade might not yield many results, but you’re essentially connecting to minio. Googling for fixes to make things work with minio could also help you out with tardigrade.