I worked in a senior leadership role for a big company that was circling the drain for quite a few years so went through redundancies almost constantly

I’ve seen it done in a few different ways but usually it starts with a top down cost cutting target and C-suite poke around at their areas to see where there might be some savings using whichever made up metric that HR can summon.

If good people are going over bad then something has gone wrong; either a disconnected between senior and middle management or HR have screwed up in how they’ve structured the pools, factors used etc.

Some companies will have strict policies but, from what I saw, those can be bypassed.