No WTF - you just agreed with me.WTF?
They subpoena people all the time, to discuss issues.
THEN, they refer to the DOJ.
Judges can subpoena, but they don't enforce their judgements - law ENFORCEMENT does.
Congress makes a decision, then refers that to the DOJ to ENFORCE.
If the DOJ decides to do nothing, like with Biden, then Congress can't do a damn thing.