To your original question, the precious metals are in a bit of tizzy right now. A lot of people buy silver and gold as an inflation hedge or to prep for a SHTF scenario. Then Covid and social unrest hit last year, and you had even more people buying it. These events boosted demand for physical silver while supply has been running short, so the premiums you see are due to demand and limited supply.
A broader question is: why hasn't this demand been reflected in the spot price of silver? Silver and gold crashed at the same time the markets did last year, then rebounded just like markets. But the markets have continued moving from one high to the next, while gold/silver have been steady.
I believe the reason is that the spot price is based on paper silver, which is independent of the price of physical silver. ETFs like SLV are supposed to be tied to physical holdings of silver, but I've never seen an accounting done to assure a paper silver holder that their ETF share sits in a vault somewhere. Many, like me, suspect the paper is inflated and manipulated more easily than the physical market.
At least since the Hunt Bros episode.