Hey @jjking, I would suggest this instead:
Have an expiry date for subscriptions in general.
When a user signs up for a free trial, set the expiry date as current time + 14.
When a user signs up for a subscription, set the expiry date as current expiry date + 30.4375 (365.25 / 12).
For the countdown of subscription days left, use magic text to pull the expiry date. Date magic texts are formatted as “Relative” by default (eg. in X days), so you’re good.
As for Zapier, it can get quite complicated in terms of the logic, but there should be tonnes of tutorials on the internet, since Zapier is a very popular product. But if cost is a concern, you can look at Parabola or Integromat, both of which work the same, but less user-friendly 