Congressional staff aren’t generally treated the same as US Congressional Reps and Senators, and most of the staff wouldn’t request anything on their own behalf when dealing with TSA or CBP beyond that which is available to the general American public.
I’ve known a few very senior Congress staffers (and way more junior Congress staffers) in my time — and even some of the House GCs, the Senate GCs and some of the Senate committees’ GCs — and they’ve been in the same TSA and CBP lines as myself on my personal/family trips more than once. They generally get treated no better than I have been on my personal trips. The actual members — not staff — of the two houses of the US Congress are often a different story when dealing with CBP, but not all of them get a receiving CBP committee or even airline escort all the time when arriving back at US ports of entries on personal trips.