Is the drain vented elsewhere, or is that the only stack? If so not leaving it open vent could cause problems.It’s protrudes out past waves at Approx 6” above head height.
Right back back door/new steps patio etc.
Just looks awful.
All the neighbours have AAV's? Even more reason to keep yours the way it is, the main shared drain needs to be vented by at least one open vented stack, if everyone else on the shared drain has an AAV then yours may be the only one venting the drain and unfortunately have missed the boat.That’s what i I said but neighbours all have it?