Apples store should have to be installed in the same way, IMHO. It should also remove itself regularly to ensure it continues to do so. Only then will the process to add and use 3rd party stores be fair.
If you don't know what you're doing, on ios you need a separate video with instructions (or fumble around) to figure out how to install a third party app, while on android the prompts guide you.
On android when you download an apk and try to install it, you get a popup saying something like "Chrome needs permission to install unknown apps." with a button to cancel or go directly to the settings and give chrome the permissions, after you enable the permissions you also get the prompt to install the apk right away. This is the equivalent on windows to just clicking next half a dozen times to install some software, on ios you have to trigger the install, go manually to the settings and enable the permission, then trigger the install again.
As a layman I doubt this is compliant with the appropriate EU laws (specifically the DMA)
Unfortunately this behaviour does not come as a surprise but I certainly hope the regulatory "beatings" will continue until compliance improves.