The biggest issue I find people have been just spending way too much time on putting on the spackle. But it’s very easy! Put on the first coat and wait until it dries. Then go for the second coat and so on. Never ever sand between coats. Most people overthink this and try to become an artist and really make it way harder than it has to be.
Don’t forget, do not sand anything until you’re done with the third coat. See sheetrock repair done the easy way.