The most important change would be
innodb_buffer_pool_size=6G --> 12G
The number of buffer_pool_instances should be 1 per GB, not one per core. So, 12 in your new machine. However, there is a limit of 16. As for why...
I suspect it makes very little difference -- perhaps single-digit-percentage when the server is extremely busy. (If a server is that ...
"Table is full" implies a disk space problem. But there are other issues:
How much RAM in your container?
not more than 1% of RAM available. Anyway, those are used during complex SELECTs; they are not used during INSERTs.
dump of size around 18GB
Depending on the datatypes, etc, etc, the amount of disk ...