The total data received from the remote client exceeded the allowed maximum. The allowed maximum ...

Those one-liners are convenient, but they don't really work in scenarios where you have thousands and thousands of users, as you've already noted. Get the list of user mailboxes, store it in a variable, then do a loop over each. If that fails as well, minimize the amount of data transferred by fetching just the bare minimum of properties you need, instead of the 200+ that Get-Mailbox returns. This can be done by using the method detailed here: https://techcommunity.microsoft.com/t5/Exchange-Team-Blog/Running-PowerShell-cmdlets-for-large-numbers-of-users-in-Office/ba-p/604280