A chat server running on powerful hardware collapsing when handling more than 100 events per second isn’t acceptable. Events scale up based on room activity from non-local users including spammers too. It’s an issue for a server with 12 users too.

https://element.io/blog/scaling-to-millions-of-users-requires-synapse-pro/

Choosing to write the Matrix server software in Python in the first place was a huge mistake. It’s now far harder to develop and maintain the software. It heavily contributes to it being buggy and fragile. It’s the biggest factor in it being so incredibly slow and hard to scale.