the commands!

1. /execute if block ~ ~ ~ chest{Items:[{id:"minecraft:ItemYouWant"}]} run say block detected

2. /execute if data block ~ ~ ~ Items[{id:"minecraft:ItemYouWant"}] unless data block -671 64 -151 Items[1] run say block detected

.3 /execute if block ~ ~ ~ chest{Items:[{id:"minecraft:ItemYouWant",tag:{display:{Name:'{"text":ItemName"}'}}}]} run say detected