Did u tested your product with users and did you pass the checkmark for launching product? There is a serious steps that you need to fill in before you actually go to market. I don’t wanna disappoint you, but it will be super hard to have revenues no mater how good marketing you take. You didn’t introduce your product in early stages and that what brings customer, so you don’t have to spend money on doing crazy marketing campaign. I am writing this based on experience because some of my clients went trough same shit because they were stubborn.
Seems like your product didn’t go trough steps of testing and researching. You can’t expect to build your product and just launch it right away and then ask yourself why we don’t have subscription :D.