Additionally, the recent resurgence of COVID-19 cases in Japan has raised major concerns regarding our ability to travel overseas for on-site implementations. These setbacks have made it difficult for us to cut down on the time required for implementation.
Not sure if you are aware of this, their is also an outbreak here in Australia currently.

Yoshi wanted to install the servers at endwalker launch, however decided that 5.1 would be better due to the current circumstances.

However with server hardware shortage and covid reeking havoc in both countries could it be pushed back further, like 5.2?