postgresql – sqlalchemy bulk update

I use
PostgreSQL 12
SQLAlchemy 1.4

I have a table with multiple columns and one column is a value which is computed in the python code before it’s inserted. Now the factors in this computed value may change after a couple of months.

player1 | country | date | rank | computed_score

I’m looking for an efficient way to loop over all rows and recompute that column. I have already looked through their examples and can efficiently fetch millions of rows but how do I update each row efficiently?