an excellent example of how not to do things. if you need something esoteric enough that no one is going to grok the crontab without thought then you use something else.
I know, with eventbridge and lambdas this problem could be alleviated a bit, since eventbridge uses cron syntax but with some added bells and whistles ( https://docs.aws.amazon.com/eventbridge/latest/userguide/eb-...) which would make the expression for the first monday of each month much easier to write.