MySQL server upgrade, how to adapt variables?
If your dataset size is only 1,3MB, then buffer_pool_size = 256M gives you a lot of  growing room.

If HDD, change innodb_io_capacity back to the default of 200.

The slowlog (which you have already turned on) will provide info on what to fix if you have performance problems.

Has the server crashed?  If so, let's see details on that.

Do you have other apps crammed into the tiny 2GB of RAM?  Changing to 8GB is likely to help with that.