Late game pvz is about map control. You need to inflict enough damage with drops to slow z down regardless. Ground mass to keep z busy choking hard even if you know you can't break. If the choke is too large and you feel you aren't doing enough damage, you need to still drop and mass but now take map especially the choke. It's hard for z to break out vs reavers, Temps, goons and mass cannons. Cannon sides of map outside the z base while massing star ports at a base nearby. I prefer scout bombs vs carriers. They come out faster and are less supply then cars. You can maintain a still high unit count of reavers and Temps at choke. You can eventually get main. It's good to also send drops with the scout bombs. After you get main, mass gates mid and rally towards the outer z choke nonstop sending goons, reavers, Temps alongside drops. It's important to get map control so z doesn't expo or have vision of another gas to dodge drops. Alot of effort pvz late game but it works. Although, keep in mind, you need to inflict enough damage early with mass and drops to keep z in check. If you don't, any good zerg player will not let you take map like that and do scout bombs.

The biggest key is recognizing if it's necessary to contain z and take main or if you can just kill z with drops and mass. It's a judgement call based off how your drops are landing and how much damage you do on choke/what kind of z player is it. Alot of z gamers rely on heavy almost seemingly unbreakable chokes. Those are the gamers where you would probably want to scout bomb late game. Other z gamers who rely on less sinks and more unit count, you need to push sooner while dropping. Very difficult for z to use units to defend vs drops while defending their choke vs reaver/goon/storm

I like Tom's triple nex pvz or Whiteandblacks fast break pvz. Tom has a good timing attack between goons, reavers and storm. Focuses on a fast 1-1-1. It makes z really focus hard on their choke and diverts all of their attention towards choke building leaving their main open for drops. Hard to multi task. I noticed that when White does his transition from 3 gate mid build to shuttle drop and reaver push, its extremely fast because he doesn't waste time with as much cannons. Goes straight tech instead of wasting resources on forge and cannons. All that with his high apm micro with zs, it becomes overwhelming for z to stop. Cole also use to have a sick pvz. Very fast mass with nonstop drops and fake drops that would distract units. Hot keying empty shuttles to fake out z's units. In the rare occasion, z survived, he would nonstop hallucinate mass temp drops on front that was very hard to stop.