2018 5.0 f150 burning oil SECOND ENGINE

I have a 2018 f150 5.0 lariat 4x4. I absolutely
love the truck it’s powerful, and and very
comfortable. I bought it with 22k miles on it. I
had a check engine light come on at 32k. Ok,
no big deal. I have a warranty. I took it in and
they said it was very low on oil. I thought it
was strange for a 2018 engine to burn oil fast.
I drove it for a while and then at 35k I would
get a rod knock for about a second when I
cold started it. I took it back and they
confirmed the engine was bad. They fixed it
under warranty. Fast forward 1 year later, it
still has the “normal” knocking sound at idle.
Just for fun, I checked the oil today. So there’s
2 dots right? Yeah, it was halfway below the
1st dot. On the SECOND engine. My 79 f100
with the 4.9 inline 6 barely burns any oil in
between oil changes. Can anyone give me
some advice? I’ve read online it’s most likely
the pcv valve. I’m making a appointment with
my dealership. I’m very disappointed.