In general yes but may stop subscriptions if there is any updates for a while

If the app is a hosted service where there are real recurring costs, that makes sense.

Otherwise, I think it's better if there is a larger one time fee. The app dev still gets compensated for the time and effort put into it, and yet it doesn't feel like a cash grab.

personally I’m fine with that, developers should get paid for their work if they want to.

It would be cooler if the app was open source of course (and even despite that the devs can still offer a subscription model).

It really depends. In the cases where I do agree, the software is usually something you'd host and you're paying for the software maintainer to host it for you with the option to host yourself.

Yes, app developers also need to pay their bills, and monetizing an app is a working revenue stream. If the quality is right and a lot of work is put into it, why not?

Case in point, I have an Ivory subscription.

depends on what based means and what the platform is, like open source onlyfans seems fine

open source projects need to get funding in some way, and subs can be one of it

Mastodon is overflowing with money and users so it's pretty sensible to make a paid app for it, considering more resources are used for its development