General help

In a word, no. The closest thing is the event monitoring rules (See https://docs.moodle.org/37/en/Event_monitoring#How_to_create_or_manage_a_rule), which let you send an email upon course completion (or many other events) - but only to yourself.

You could ask a developer to create a local plugin which implements an autoresponder. (Just don't ask them to duplicate Mailchimp wholesale though, as that would be prohibitively expensive, and send them the wrong signal that you're maybe not serious about this.)

There are a couple of plugins for Moodle that can trigger a web hook when a Moodle event occurs. You can use this to ping a service like Zapier or IFTTT which will then relay your information to MailChimp (or Infusionsoft or whatever) to set up the autoresponder sequence. I know thats a head spin at first. But the result is that you can set up auto responders based on events in Moodle without any coding at all.

You can see some discussions about those plugins here:
https://moodle.org/mod/forum/discuss.php?d=378947

each instance of the Reengagment activity can be configured to send the same e-mail text multiple times on a schedule, however if you want different text to appear in each email (eg a different tip) you would need to set up multiple reengagment activity instances in your site. - one for each "tip"

It might be possible to do this with reengagement but I'm not sure it would be the most efficient - I'm not aware of anything else built into moodle to facilitate this (although Justin's suggestion of zapier/ifttt could be an easier way to do it.)