Wrong on 2 accounts.I can find the troops without a stupid theory.
Common sense finds a few hundred Dothraki and a Unsullied soldiers not at the battle to add to those who survived it.
Soliders left behind to guard other castles, lands, injured soliders from previous battles left behind.
You don't think the Battle of Goldroad left behind a heap of injured soldiers?
From the battle:
So you think they are going to drag a heap of injured soldiers North with them? Nah.
There was no re-spawning.
Firstly, Dany needed every single solder she could muster for the Army of the Living. That was the whole reason for her trip to KL, using the wight to (unsuccessfully) convince Cersei to send her army north. Dany wasn't leaving half her army scattered around Westeros, when they were so desperately needed in Winterfell. She knew they were quite literally facing a battle for Life or Death. If she lost that battle, it wouldn't matter if she still had some reserves scattered around the continent.
Secondly, we saw the commanders - first Grey Worm, then Jon, then Yohn Royce, then the Dothraki commander, removing their markers from the map, after the battle. Grey Worm says he has "half" his force remaining. He's clearly indicating that half of his forces survived the Battle of Winterfell, not that half of them are scattered all over Westeros.
Given the massacre we witnessed in ep #3, the only way to explain how "half" his force was still available for the Battle of Kings Landing was re-spawning (or cloning vats). The same also goes for the other armies (Northmen, Vale, Dothraki).