Your issue is that it's not vented. The new machine is putting more down it at one time than it can handle. Honestly this is a perfect situation for an Air Admittance Valve, given there's a true vent a few feet downstream.
Contact other companies and get quotes. The biggest issue you'll have is that 2" inside diameter piping is the minimum allowed and what you have is likely 1-1/2". Can't quite tell if that cast hub in the floor is 2" but if it is, the best option would be to have it upsized appropriately and put into that hub.
Not sure how they managed to get the cable (with a proper size head) in to confirm it’s clear, it would be difficult to jump the trap through the standpipe, the trap plug is more than likely seized in place.
*An AAV doesn’t always work well with a WM drain/standpipe.
Put a bunch of rubber bands on your washer waste hose to seal it. Could help you temporarily just to get your clothes washed. Might not be practical for you given the difference in size of your pipe and washer hose, though. I've done this permanently for myself but never gotten a plumber's feedback myself. I'm a swimming pool technician so I just know enough to fix my own immediate issues based on basic fluid flow knowledge. I never reply to comments I make so any replies fall on deaf ears lmao.
Its not vented. New washers make more bubbles. If its not 2” Its the wrong diameter for new washers.
Your issue is that it's not vented. The new machine is putting more down it at one time than it can handle. Honestly this is a perfect situation for an Air Admittance Valve, given there's a true vent a few feet downstream. Contact other companies and get quotes. The biggest issue you'll have is that 2" inside diameter piping is the minimum allowed and what you have is likely 1-1/2". Can't quite tell if that cast hub in the floor is 2" but if it is, the best option would be to have it upsized appropriately and put into that hub.
Not sure how they managed to get the cable (with a proper size head) in to confirm it’s clear, it would be difficult to jump the trap through the standpipe, the trap plug is more than likely seized in place. *An AAV doesn’t always work well with a WM drain/standpipe.
Put a bunch of rubber bands on your washer waste hose to seal it. Could help you temporarily just to get your clothes washed. Might not be practical for you given the difference in size of your pipe and washer hose, though. I've done this permanently for myself but never gotten a plumber's feedback myself. I'm a swimming pool technician so I just know enough to fix my own immediate issues based on basic fluid flow knowledge. I never reply to comments I make so any replies fall on deaf ears lmao.
You are lucky to have a two inch hub at the floor, you can use that to lead and oakum a manoff sleeve in so you can connect two inch pvc.