What do you think is the connection between the knock sensor having low voltage and a bad cam position solenoid?

I agree with you. Direct communication should not be.
The only connection I see is that both errors arose with a difference of 1 week immediately after oil starvation.

I removed the problem
the error disappeared and does not appear two week
Solenoid No. 2 (exhaust manifold) was removed, washed with WD40 and preventive bathing in a bowl with gasoline overnight.
In the morning I stuck it in its rightful place - while it works fine, but I ordered a new set of solenoids, just in case.
Knock sensor is also fixed. Its connector contained a problem. This connector hangs very close to the ground, snow and dirt get inside and break electrical contact. The treatment is simple - dielectric grease.
The fact that 2 different problems got out at the same time is probably fate.
And so, my Hippo is again vigorous and contented.