Theoretically, a cheap option is to modify Starlink with enlarged argon tanks to rendezvous and "shepherd" large debris into lower orbits. Add LiDAR (DragonEye) and "Push Me Pull You" argon thrusters and it can exert a gentle push even when the debris object is uncontrolled and tumbling.
I'm somewhat surprised SpaceX hasn't tackled this problem yet. Even including just one StarCleaner every 2-3 Starlink launches could make a huge difference.
SpaceX even has the perfect test satellite. RatSat was their first successful launch in 2008, and it's barely decayed despite saying it would only last five to ten years.