I would like to provide a response to the topic I originally raised in order to document the progress and be of public utility to anyone who may come across the same question.
Firstly, I want to acknowledge that I mistakenly clicked the wrong tag when I initially posted. I was actually using 22-04 Jammy LTS.
Recently, I came across some information about Marco and encountered an issue on github which shed light on what might be happening. It appears that some tweaking or hacking may be necessary in order to avoid sharp edges from the windows manager. Unfortunately, the problem remains unresolved at this time.
However, I did come across the wonderful project Ambiant-MATE Family, which brings back the classic Ambient theme into 22-04. This elegant theme has effectively eliminated the issue of sharp edges for me, and I am now very happy with the appearance of my system.