it's not making a "level playing field".
it's about forcing changes that stop making Apple do things that many customers buy their products for.
if i wanted a device i could install anything, i had a choice. i would buy an android device.
many like the fact Apple vet apps and have more control to stop spyware and bad actor code getting onto devices.
the EU forced that change without regard to those who wanted this feature.
Because this isn't about competition between iOS and Android, but competition between all kinds of services. Maybe someone can figure out a better service than Apple Wallet, maybe not, but at least there's the possibility, which will also keep Apple on their toes.
It's a convenient argument to say that if people wanted x, they would have just bought a different device, but I don't think that's how people actually make these decisions. Something like Apple Wallet is largely interchangeable with possible competition on either really new and innovative features, or alternatively where Apple Pay just isn't available in a specific country. No one is going to switch their device ecosystem because they really want to use Google Pay or Apple Pay. If you were forced to use an Android phone tomorrow you'd install Google Pay or Samsung Pay and you would probably go on to live your life just fine, hence there just isn't competition on an ecosystem level.
So really the only way to enable competition in these areas is to allow people to pick and choose on the device they already have, which includes Apple. Everything else just doesn't work. Smartphones have become way too central to our lives, way too ubiquitous and at the same time way to locked down to only rely on ecosystem competition to keep everyone in check. That might be good in the short term because an integrated ecosystem can be incredibly convenient, and from a personal perspective I can absolutely understand how forcing everyone to support core platform services enhances the user experience, but in the long term it'll kill broader innovation and concentrate an incredible amount of power in the hands of just a few companies.