I've been reading a lot of eMMC datasheets and I see terms like "static data refresh" advertised quite a bit.
You're quite right that we have no visibility into this process, but that feels like something to bring up with the SFF Committee, who keeps the S.M.A.R.T. standard.
Might need to go through the NVMe consortium rather than SFF/SNIA. Consumer drives aren't really following any SFF standards these days, but they are still implementing non-optional NVMe features so they can claim compliance with the latest NVMe spec.
You're quite right that we have no visibility into this process, but that feels like something to bring up with the SFF Committee, who keeps the S.M.A.R.T. standard.