How can I remove 3-way switch to leave single pole switch on the lighting circuit?
I was able to get it working with the following changes:

For the switch being replaced, connected the black wire to BK, the other black wire to RD, and the two white wires that were capped together are now connected to WH on the new switch.

For the switch being removed, left two white wires capped together and capped two black wires together.

The red wire is no longer used on either end (switch) and is now capped.