Okay,
so I know DT has their glass coated magnet available but its too big and weak to be a de facto sensing magnet
There is a video of Amal explaining why TiN, gold and silicone are not quite perfect yet either. TiN has holes, gold corrodes, silicone breaks
from what I know you canelectroplate rare earth magnets. Why not plate with platinum, iridium, or the alloy of those two. Those have beenlong proven to be safe by the medical industry. Pacemakers are partially platinum or platinum-iridium
Platinum is expensive. The cost would definitely be high, but they would last some time and essentially be medical grade. It seems like no one cares about iridium because I cannot find any info about electroplating it.
A smartwatch is like 400USD for example and “lasts” less than five years for most people before they upgrade.
The only issue I can think of is it having holes just like the TiN