An SQL query goes through multiple stages to be executed. This is a wide topic, but in summary, multiple execution strategies are proposed for each query, they are evaluated, and one is selected for execution, and finally, it is executed.
We can see an SQL's query plan using PostgreSQL's
EXPLAIN ANALYZE here https://www.postgresql.org/docs/current/using-explain.html.
I was wondering if it is possible to build the plan manually and then execute it. In other words, as a user, I won't use SQL nor the query optimizer features offered by PostgreSQL. Instead, I will manually construct the query plan and execute that. I would figure that PostgreSQL would have such features for debugging or an extension would exist, but I can't find such functionality.