From Bombardier-Alstom, there are several designs, with single and bi-levels. Very pleasant interiors seen in photos.
https://www.railjournal.com/rolling-stock/alstom-and-bombardier-unveil-new-french-rer-train/
3-2 seating isn’t all that popular in the United States, I think that only Metro North uses it. I would not like to be stuck in the middle seat.
I lived in NYC in the 1960s and early 70s. If I remember correctly, the Long Island Railroad trains had 3-2 seating, at least on the Flushing line.
I’m sure the seating charts can be modified to avoirdupois considerations.
Hope the seats are more comfortable than they look.
All single-level MARC cars have 3/2 seating. You are right that the middle seat is highly undesirable. Thankfully, all bi-level cars have 2/2 seats; gallery-style cars purchased from METRA years ago have been retired from service. MARC links the Maryland suburbs and West Virginia’s Eastern Panhandle with Union Station in DC.