I think this is a "drum trap", is that right? I'm smelling sewer gas, should I replace it?

Since we moved in we've noticed a sewer smell from time to time. I had a plumber come and identify this laundry discharge pipe not having a trap as the culprit. He ended up ghosting me so I cut more into the wall and found this black thing I couldn't identify until now (I think). I guess it's a drum trap after doing some more googling. If it's working as designed I guess it's supposed to hold water in and not let sewer gas through? but we definitely have a problem with the smell coming from this laundry room. Is this maybe not to culprit and I could leave it alone? I'm considering cutting it out and just connecting PVC the whole way through. Any recommendations or thoughts would be much appreciated.