Yes, data scrubbing (read only) is still a good idea for SSDs. If data in a marginal memory cell is starting to degrade, reading that data will cause the SSD to notice a correctable error and write a fresh copy of the data. Simply leaving the drive on the shelf would put you at more risk of degradation leading to an error that the drive was not able to correct (though a RAID layer above the individual drives may still be able to recover the data).

Many drives will do some amount of background reading on their own to scan for degraded data. But this isn't visible to the host system and not guaranteed, so it shouldn't be relied upon and doing some extra reads (eg. once a month) is harmless.

I strongly believe QLC SSDs are a great choice for NAS usage, unless it's very frequently modified data. It's still more expensive than hard drives, but the noise, power and performance benefits can be worth it.