If Apple inexplicably chooses to sell iDevices so cheaply that they can't afford to pay the people who build the software for it, that's their mistake. The EU isn't forcing them to do that, neither are app developers. They've had years to remedy any pricing mistakes they made in the past and price their hardware appropriately.

They also pull in billions of dollars every year from their 30% cut on gambling/gacha games, and do almost nothing to earn that (those games have to provide their own updater/CDN because the Apple/Google ones aren't good enough, and those games don't meaningfully rely on Apple/Google for things like quality assurance or marketing.) Apple will be fine even if their Europe-specific cut is halved.

Claiming they're going to suffer or be unable to pay employees is simply not supported by any evidence.

If they can't fund OS development without their App Store profits, which I highly doubt, then they should charge more for their OS.

It cannot be a valid argument against regulation that your monopoly product supports other nonprofitable parts of your business.

Such constructions are hurting competition and maintaining the status quo. It is very difficult to compete against a product which is priced unsustainably cheap.

Profit from the iPhone business alone should be much more than enough to pay those OS/framework developers since Apple claims that iOS and iPhone are indivisible/unsubstitutable parts to each other.

Yet they managed to do this for years for free when they had their walled garden up and and supposedly offered so much value to developers with their app store and such

Ideally you want your customers to be your customers and not your products. That way, the incentives are aligned