AFAIK, most Lemmy instances are running on single machines. Either dedicated servers, or virtual private servers for some smaller instances. The infrastructure is far from the level of on-demand scalability, sharding databases, and globally distributed CDNs that corporate social media platforms like Facebook, Reddit, and Twitter rely on. There will be growing pains. These servers are probably getting 10 times the load they do on an ordinary day. The volunteers who make this shit work will respond in time, and the door is open for any hackers in the community to contribute (particularly if you know PostgreSQL, Rust, or TypeScript).