I have a dell laptop that uses a usbc port to charge, but doesn't actually use the PD specification, but a custom one, so my 65w GAN charger falls back to 5v 0.5a and isn't useful at all. I'd bet dollars to donuts that your Lenovo is doing similar shit.

No. It can charge from my monitor PD just fine.

And wow, I'll keep away from Dell, thanks.