No enough room for slope

Recently we put in new washer/dryer units, but due to the direction the doors opened, we ended up reversing the order compared to the old units. This put my washer farther from my drain pipe.

My units are in the basement. My drain pipe runs along the ceiling of the basement. I do have some slope, probably not quite enough for the drain to function properly.

More and more, my washer is not draining properly, and I meet all the regulations in the manual for drain height/length, so my guess is its the slope of the pipe. Problem is I've reached the end of my house, with no room to add slope.

Tl;dr How do you add slope to your drain pipe when you run out of room?

If needed, I will go take measurements of everything.

What amount of slope do you have?

Why not just reverse the doors on the appliances? Almost all are reversible. Little bit of work, but easy enough. Last dryer door I reversed had 21 screws(!).

I'll look at the doors, but apparently there was another problem with the washer, so we called in our once a year maintenance, and apparently the amount of water in the washer is normal for this washer. Thanks for the help