The noise problem can be partially solved with fan profile in the bios on the dell. Have an R-610 close to desk and it helps mostly runs quite at this point basically for BU.
You say you want to upgrade your storage but don’t provide and direction. This would make any recommendation rather pointless. What is the use case? Are you having capacity issues? Performance issues?
What is the use case: File storage for emby, Surveillance, pictures, 5 iscsi targets (Game storage, Nextcloud, some docker images)
Are you having capacity issues: I am down to 1TB of free storage.
Performance issues: none as of right now
If you are running low of storage for me it would really come down to cost. Is it cheaper to add a HBA, Shelf and a bit more RAM or is it more cost effective to build another unit and move some of the data over.