
For an anonymous email, Tuta should be good.
Protonmail is also an alternative, but that one requires you to have another email address iirc.
Both of these are European.
Be aware that if you use an email for personal business, like buying stuff online, your email address will be connected to your identity indirectly regardless. So it depends on what you are going to use it for. It might be that it won’t matter (in your case) that the address is linked to your identity through the phone number if you are already linking it to yourself in other ways.
Imagine calling a house a pod.