If you go for horizontal scaling like that, indeed everything needs to be adjusted. If you're asking "is your DB setup to handle 100x increase in load" then likely the answer is no. "How do you shard your writes" is likely a better question then... Aggressive autoscaling requires different thinking.
Depends on how many times you've scaled 100x already. 1 user to 100 users is 100x, 100 users to 10k users is 100x, 10k users to 1 million users is 100x. Aurora serverless autoscaling can handle a LOT, depending on the architecture and use case.
