Most apps shouldn’t be subscriptions. They should cost money once, like buying a hammer.
The subscription model assumes ongoing cost on the developer side and ongoing value on the user side. For most utility apps, neither is true. You wrote it, you ship it, the user uses it for years. Charging them every month for that is rent-seeking dressed up as a business model.
When subscriptions make sense
Server-backed services. Apps with content that ships continuously. Apps where the developer is genuinely on the hook for ongoing infrastructure costs proportional to usage.
When they don’t
Camera apps. Note apps. Habit trackers. Run timers. Most of what gets shipped to the App Store. These are tools. You should be able to buy them once.