Armchair general opinion here, but basically: It pretty much doesn’t matter how much armour you pile onto something- it adds weight, fuel costs, and reduces speed, and all the armour in the world will still only last a limited amount of time against powerful explosives specifically designed to destroy armour. The most basic thing about armoured vehicles is doing something in the time that that armour buys you. And to do stuff, you need speed, firepower, and a good optics system.
The Bradley has those three things in spades. Even if it’s not the most heavily armoured vehicle ever seen, it’s really fucking cost effective, WAY easier to maintain with Ukraine’s more limited resources than the US army, and versatile as hell. It uses the time that it has before the armour inevitably fails exceedingly well.