Something that has always bothered me an outsized amount is Elasticache.

I will bite the bullet and pay for RDS because it adds a lot of value - scalability, a reasonably optimized config, backups I don’t have to worry about.

But Elasticache is exploitatively priced with almost no value add.

It is slower, less optimized, less stable, and only supports one DB compared to a vanilla redis install with zero configuration.

There are some scalability improvements, but it’s extremely rare they’re even required because vanilla redis so wildly outperforms elasticache on a similar instance.