Writing to the database - why does the speed of operations drop?

Question

MySQL

The situation is as follows - I have an excel file with 600k lines, parsed by a PHP script (symfony console command).
I use Doctrine, I write to the database in batches of 200.
The environment is aws eb, mysql SSD.
The UUID is used as the primary key.
I observe a gradual decrease in the speed of operations (for the first hour - 24k were exported, for the second - already 19k, etc.).
Where to dig?

Answer 1

I propose to stop torturing all sorts of ORMs, save the excel in csv and use LOAD DATA INFILE

LOAD DATA INFILE 'data.txt' INTO TABLE db2.my_table;