How to ensure parallel execution spreads across RAC instances if parallel_force_local=true

At a 4-node RAC with Oracle Database 19.25 parallel execution is intentionally limited to single node by setting parallel_force_local=true globally for all RAC nodes.

In contrast to this default settings I want a particular session to use the CPUs of all RAC nodes.

Setting ALTER SESSION SET parallel_force_local=false; as mentioned in the documentation has no effect.

SQLs like this still use the PQ servers only at the REC node the session is connected to:

SELECT /*+ PARALLEL(4) FULL(b) */ Count(*) FROM table b;

What else needs to be done to restore the default behavior (PQ across RAC nodes) at session level.