I don't understand what people have against subscriptions.
To me that's the fairest. First, it incentives them to make a good product, and keep developing it as opposed to just throwing it out there and then not updating.
And secondly it's also fair for the customer. If I don't find something useful I might stop using it after a week, but I paid the full price, same as if I found it useful for years.
On iOS, it gets even worse as there never were high prices to begin with. Which means that the OTP model was never very sustainable.