We have built several storage server using Microsoft Storage Spaces, and have had good results. Our need has been for a backup and restore target for our Veaam that could really speed the process up. The key ingredient is tiering with SSD's, we used SATA and later SAS drives, and we have started testing using NVMe drives in the 2.5" U2 form factor. The best document I have found was put together by Veaam and posted on their user portal, I have tried to relocate it but have been unsuccessful so far.
Another issue is all the new write-up is on Storage Spaces Direct, and pretty much skip over all thin fine details.
From memory I will mention some things that stood out from the Veaam recipe.
Although not called a specific RAID set, the closest we did would be likened to a RAID10.
So for every spinning disk you need a SSD for best results, we used both 480GB and 960GB and did not see much performance difference, spinning disks we used were the Seagate Iron Wolf SATA 8GB, later we changed to the Seagate Exos SAS drive in 10TB, and later build the 16TB
All drives must not be on a RAID controller unless the controller can be set so that the drives pass through and presented to windows directly (HBA Mode)
I have created a pool as small as 4/4 (4 SSD's and 4 Spinning disks, 2/2 mirrored to the other 2/2) and as many as 16 and 16.
Really performance wise we did see some improvement sending 8-10 simultaneous backups to many small 4/4 then 40 to the larger16/16 disk pool.
We set our format to ReFS, unit size to 64k
A common issue we had was the pool/VD not attaching after reboot.
Here is the artical we used on the fix https://dannyda.com/2019/12/27/how-to-fix-windows-storage-space-storage-pool-virtual-disk-not-attaching-automatically-on-reboot/
Hope this helps some.
:)