You don't need to log every auto explain. Just enable track_io_timing and pg_stat_statements and you get per query IO performance metrics much cheaper.

Table F.21. pg_stat_statements Columns

https://www.postgresql.org/docs/11/pgstatstatements.html

blk_read_time

double precision

Total time the statement spent reading blocks, in milliseconds (if track_io_timing is enabled, otherwise zero)

blk_write_time

double precision

Total time the statement spent writing blocks, in milliseconds (if track_io_timing is enabled, otherwise zero)