inno_db_buffer_pool_size and key efficiency
If your tables are InnoDB (not MyISAM), innodb_buffer_pool_size should be about 70% of available RAM.  However it does not need to be much bigger than the total Data_length and Index_length for all your tables.

It does not hurt to make that tunable "too big" unless you need the RAM for something else.

If you would like further analysis, please provide SHOW VARIABLES and SHOW GLOBAL STATUS.  From that, we can sort out which engine the vague "key efficiency" refers to, plus check other things.  (I have automated about 200 checks.)

Also, it is unclear whether "InnoDB writes per second" is INSERTs or disk writes.  Since you have SSDs, it could be either.