While I love to take potshots, the yes(configurable) next to that 100gb does some heavy lifting.
I imagine that number is tunable up to multi digit tb if you your monthly bill is worth Jassy's attention
https://docs.aws.amazon.com/aurora-dsql/latest/userguide/CHA...
The more interesting (i.e. constraining) limits are transaction size (both row count and data size) and transaction time, which aren't configurable.