There's no formal hierarchy so there's nothing technical about it. Field's medal is certainly prestigious but it's not widely applicable, it has a bunch of rest

There's no formal hierarchy so there's nothing technical about it. Field's medal is certainly prestigious but it's not widely applicable, it has a bunch of restrictions that don't have anything to do with math itself, including an age limit. For example no one who has ever been awarded an Abel Prize would qualify for a Field's medal strictly due to age.