Extra tip: alpha chest and normal chests don’t spawn in same shovels, so if you found any normal chest, then stop digging because you can use the remaining shovels next time because you might run out of shovels even if you found an alpha chest!
another tip with the reroll option: If you get a normal treasure chest, dig it. You can reroll it and have a chance of getting an alpha chest. Coming from me a person who has gotten it 2 times thanks to the treasure chest and reroll option
Flying animals don’t actually help that often from what I’ve found, because flying can obscure the front part of the world and shovels spawn there sometimes. This is especially true in serpia forest and temple of zios.
I think once you get one it becomes easier to get more it took me around 400 shovels to find my first one the found 2 more alpha items the following 3 days. This is the case at least for me. Gl alpha hunting! :)