So thankfully, it looks like the new cable has fixed the issue.
My first initial use of the new sync on luma cable didn’t show any improvements. I still had screen juttering when deblur was enabled. However, I’ve been using it for two days now across multiple different games and I haven’t noticed those issues at all. I’m not sure if I messed with something in the OSSC settings or if the cable is just doing the job correctly now, but I believe the situation has resolved itself.
Thanks for reaching out and I’ll report if there’s any changes.