Fastest mechanism to move data between tables in SQL server
The better way wqould be to fix the broken programming requiring a total re-transform of all data. THat is a terrible non-scaling approach to start with and whoever justified that - I hope they now work in another field, as far away from any project responsibility as possible.

If you use enterprise edition you could possibly use a partition and partition swaps - even with only ONE Partition that at least has some schema lock optimizations. The schema of the table never changes. It has negative implications on statistics, though, before SQL Server 2014.

At the end it really runs down to a non-competent approach that was choosen - those "smart shortcuts" always come back to bite you.