Small, double boxes well packaged items ie. CDPs, CD transports, etc I’ve had good luck with.
Several years ago I bought, from a seller with a record of good feedback, a pair of B&W 802, Matrix II Speakers, to be shipped half way across the country. I bought insurance for $2K, my cost of speakers, plus I had the extra expenses of professional packaging (through UPS) and shipping. When I received the speakers both boxes, as well as the speakers miid range and tweeter sections were crushed, as if dropped upside down 6’ from the back of a truck and completely destroyed. At first UPS refused to pay anything and after several days of haggling said they would settle with seller for $1K, half of the insured amount. My lawyer informed them that once I paid for the speakers, insurance and shipping, they became my property and they would deal with either me or we would file a suit for their willful mis-handling and destruction of my property. I received a check within 10 days for the full amount of insurance - $2K.......Jim