Local auctions are better shots for estate coins than
ebay, by far. These auctions are usually posted in local newspapers or (nowadays) online. This is especially true for court-ordered sales where there were no remaining heirs or the probate court could not elect an executor/heir to dispose of the estate.
In-person estate sales are a risk, most people who do estate sales for a living have "preferred" customers for certain categories who get early access to things like guns, sports cards, knives, fishing lures, cars, coins, records, books, etc. Those are customers who will always come in and buy the entire lot sight-seen or sight-unseen, avoiding the estate sale agent the hassle of having to tag and sort each individual item, and it often benefits the recipient of the estate sale's proceeds as well. This can make it hard for individuals not in the "group" to gain access to some of the choice items at sales. As an example, when I did the one for my parents' estate, the records, guns, boat, books, and sports memorabilia were reserved for preferred buyers (who were given early entry numbers) a week+ before the actual sale (the record buyer, e.g. paid $500 sight unseen for all of the records just based on a list.) This way, when the door opened, they simply walked in, picked up all of the items, and paid.
Most of the time when you see "estate" listings on
ebay it is a scam, but not always. The key is to look for sellers selling out of their usual category. I've scored a few great coin deals from non-coin sellers who were either antique dealers, estate sale brokers/agents, "pickers", or people who were legitimate heirs of coins from estates and did not do their homework or just didn't care. Someone who's been selling nothing but clothes on
ebay for 4 years and suddenly lists 20-30 raw coins without the usual keyword fluffery is likely to be a better shot than someone who's sold 2k coins in the last 6 months and doesn't touch anything else.