Server API Limitations Clarification

I think my question got lost in the noise of all the bots spamming the community because it never got answers. I'll repost it here:

I see there are 2 answers to 2 different questions around server api limitations

https://community.playfab.com/questions/66702/detail-of-server-api-limitations.html

The question and answer seem to indicate that servers can make 1000 api calls per second. This would be ideal for me as my servers can handle up to 4000 concurrent connections.

https://community.playfab.com/questions/30828/server-api-limitations.html

However, this question and answer seems to indicate the server is limited to making 3 api requests per second. This would not be ideal for me and would take too long to authenticate all new incoming connections and update player statistics. CloudScript was offered as a potential workaround in the previous question with 25 per second, but still doesn't seem ideal.

So I have 3 questions:

What are the official server api and cloudscript call rate limits?
Based on the answer to 1, what is the best way to handle authenticating potentially 4000 session tickets and updating player statistics on potentially 4000 players at a time? Are there any batch apis that servers can call?
Are server apis limited based on ip address or developer secret token?

The details for the apis I am using in particular are as follows:

https://learn.microsoft.com/en-us/rest/api/playfab/server/authentication/authenticate-session-ticket?view=playfab-rest

This one I use to authenticate players before they connect to a game and to retrieve their currently equipped items in their inventory. A single server can support up to 4000 concurrently connected users. So it is possible for 4000 users to connect to the server at the same time causing the "AuthenticateSessionTicket" api endpoint to get invoked 4000 times. This is the most important api call that I need to happen fast and to be able to handle many connecting users.

https://learn.microsoft.com/en-us/rest/api/playfab/server/server-side-cloud-script/execute-cloud-script?view=playfab-rest

This one calls a few PlayFab APIs from within the cloudscript per player that is passed as an argument (up to 4). Ideally faster is always better, but I can live with throttling this one over a period of time if we have to. It is called at the end of the 5 minute match.
server.GetTitleInternalData
server.GetPlayerStatistics
server.GetUserInventory
server.GrantItemsToUser
server.UpdatePlayerStatistics
server.GetUserAccountInfo
entity.SetObjects