I think it's more of a "willing to put in a consumer product" issue than that they're unsolved issues. Other brands don't have the automatic sales that a product with an Apple logo has at whatever price, even for a "Pro" product that can be more expensive. Meta just can't sell a $3500 headset no matter how good were to be.
MS and Google are also continously fined billions by the EU over anti competitve and anti trust practices and, so they don't get particularly preferential treatment.
The issue here is that Apple only allows devs to let users sign up for their service through Apple. Apple also demands 30% of the subscription fee when doing this. They don't allow a developer to have a button in the app that allows to sign up through their website, or to mention that you can sign up through a website.
So the devs only have two options aside from not having an iOS app: Eat the cost and lose 30% of income to Apple, for who it's basically free money. Or charge the extra cost over the normal price to the user.
The EU has rules against this and to do business there you need to comply with those rules. Multi billion companies basically ignore those rules until they get fined, which in most cases is just considered cost of operation. After which they may or may not continue the practice if the fine is lower than what they'd lose by stopping.