MySQL - Restore 1TB database using myloader
I think it is choking on 200 threads.  Recommend not using more than twice the number of CPU cores you have.  And even that may be too high...

In particular, there is no use adding more threads after saturating the I/O.  (I am not familiar with your configuration, so I cannot be more specific.)

innodb_buffer_pool_size =235G is dangerously high for 244GB of RAM.  If there is swapping, that could be killing performance.

If you have "indexed every column", that is another performance killer for loading.  And "indexing every column" is usually useless.  Instead, discover what indexes you need, and have only them.  This often includes 'composite' indexes.

Also, multiple UNIQUE (including PRIMARY) indexes on a table is costly.