Full Disclosure: I don't watch The Boys because it's gross and, as my name suggests, I'm better than all of you.
As far as I am aware, Homelander is still coasting off of the comment that he can't be harmed by conventional weapons.
I've seen some people give him MOAB durability for that. I personally think that's wank. Especially after seeing Mave do (admittedly very minor) damage to him, and the strong implication that a point-blank blast from Soldier Boy would end him.
Homelander wouldn't do any better than the best we saw at the UA entrance exam, imo. He'd get washed by the time of the Sports Festival. Maybe even the camping trip.
I kind of doubt that he could actually hurt Muscular. Nobody in his verse can seriously wound him physically, so his DC can't scale to his own durablity. Unless one of his recent breakdowns lead to some serious self-mutilation or something.
If you assume he scales to showings from his multiverse counterparts in the animated series, the MOAB claim becomes more believable. We see a distinctly weaker hero part clouds. That said, we also see said hero die (violently) on impact with a solid object. So...durablity is inconsistent at best.