Windows Server 2019 has an interesting feature that allows you to group your drives together and create Storage Pools. It even allows you to create tiered storage (that is, specify which drives are fast (SSD) vs slow (HDD)). I've always built my RAIDs using hardware (Dell PERC). So why would someone use Storage spaces in Windows Server? What's the benefit? Would you still create a hardware RAID and then also implement Storage Pools?
Generally speaking you will want to keep hardware- and software based storage solutions separate: Both want direct access to the disks to do their job properly, and there's a high chance they'll trip each other up if combined. The general recommendation is to use an HBA rather than a RAID controller for software driven storage.
A - or rather the - benefit of hardware RAID is that a decent controller offloads work from the CPU.
This, of course, is a lot less of a problem with today's multi-core, multi-GHz CPUs than it was when server CPUs had single cores and operated in the tens or hundreds of MHz. In fact, companies like VMware and Proxmox actively encourage the use of software storage solutions for many workloads, and there are companies like Backblaze that make their entire living off storage which doesn't use hardware RAID controllers.
From what I gather, Storage Spaces plus ReFS have matured a lot in the last few years, and Microsoft's sales pitch for it looks very similar to, for example, that of VMware's for vSAN. Be aware that this solution doesn't seem to be marketed as a general purpose file system yet: it still lacks features you'll likely miss compared to NTFS.