database is not responding for hours trying to import a 2mb csv with MariaDB
Either there is a bug, or the system is ferociously swapping.

Do not blindly increase settings.  How much RAM do you have?  It sounds like you have over-committed RAM and are in the throws of heavy swapping.

innodb_buffer_pool_size = 2650M  -- OK if you have at least 6GB of RAM
innodb_log_buffer_size = 512M    -- go back to default
bulk_insert_buffer_size = 2048M  -- go back to default


All of these could be allocated simultaneously, adding up to 7GB, which would be tight in 8GB of RAM.  If you had multiple connections, running, the last one could be allocated multiple times, thereby needing even more RAM.

As a rule, anything named "buffer" or "cache" does not need to be set to huge values.  Large values help, but there are "diminishing returns".  When large values lead to swapping, performance suffers severely.

These may be directly relevant to loading a CSV file:

max_allowed_packet = 1M  -- change to 4M (due to the nature of your data)
net_buffer_length = 8M 
read_buffer_size = 5M 
bulk_insert_buffer_size = 2048M  -- go back to default (8M)


If you expect 1.8MB of spaces to be put into varchar(255), well, it will be truncated.

Which Engine is the table?