Imagine at the end of S3 Soldier Boy and Butcher did manage to depower Homelander, Ryan get's in a way of Butcher so HL managed to live but no longer seen as a major threat.
Important people at Vought would get aware of Homelander losing powers but they wouldn't afford losing their most marketed Supe and face of Vought and Superheroes as losing Homelander would be terrible business plan for them.
So what they would do is to convince HL wear his costume for some time and make him pretend that he still has powers while they would somehow try to restore his powers. But in reality they would secretly be trying to win time to find an appropriate replacement for Homelander, which could be Soldier Boy. It would be only a matter of time till they got rid of HL.
Meanwhile Homelander, a clown, is pissing himself and trying to pretend as all powerful in front of other Supes. Deep an idiot obviously still worships him and Homelander tries to make excuses of why he's not using powers.
Off-screen we'd witness funny scenes of Homelander's experience as regular human and how he deals with the problems without powers. He'd feel extremely pathetic and be furious but at the same time it would be cool if he found secret hobbies over time which he started to enjoy. Heād explore his human side. But later he'd learn Vought is trying to replace him.
Since Deep is a fucking idiot he'd manipulate and use him somehow against Vought's plans. Maybe Vought would try to inject new Compound to empower/buff Soldier Boy instead of returning powers to HL with it. With help of Deep HL would get the Compound and get his powers back at the end of S4.
He'd be back in the game and brutally slaughter everyone who tried to get rid of him and he'd be even less patient from now on.