Unified just means memory is shared which makes for very fast access. Sure, there's some deduplication. However, the 10-12GB physical+swap usage I mentioned was with the M1 MBA already. The 500MB-1GB RAM used by specific websites (Safari) were from Activity Monitor. Sadly, webpages have gotten seriously bloated. Mind you, the A12X/Z uses unified memory as well.
This message is from an iPad with 4GB RAM. You've got an extra 2GB of leeway with the 2020 iPad Pro so this page would probably have loaded there instead of crashing. However, open enough tabs and apps and you're still gonna hit reloads unless Apple implements storage-based swap file. 8GB and 16GB RAM gives even more leeway.
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