https://s3.cointelegraph.com/uploads/2021-01/2a2b7555-c10d-4a65-a812-6f5fb8b32b81.png

According to this chart, the Ethereum blockchain is busiest from 1 PM UTC to about 6 PM UTC average.

https://cointelegraph.com/news/here-are-the-best-and-worst-times-of-the-day-to-use-ethereum